1. Count of strings that can be formed from another string using each character at-most once
  2. Initialize an ArrayList in Java
  3. Finding n-th term of series 3, 13, 42, 108, 235…
  4. Find n-th term of series 1, 4, 27, 16, 125, 36, 343 .......
  5. Delete all Prime Nodes from a Singly Linked List
  6. Implement a stack using singly linked list
  7. Delete all the even nodes from a Doubly Linked List
  8. Probability of rain on N+1th day
  9. Probability of a key K present in array
  10. Count pairs with Bitwise OR as Even number
  11. Count pairs with Bitwise AND as ODD number
  12. Count pairs with Bitwise XOR as ODD number
  13. Check if a key is present in every segment of size k in an array
  14. Delete array element in given index range [L - R]
  15. How to randomly select rows from Pandas DataFrame
  16. Find Nth term of the series 0, 2, 4, 8, 12, 18...
  17. Find Nth term of the series 5, 13, 25, 41, 61...
  18. Find Nth term of the series 3, 14, 39, 84...
  19. Find Nth term of the series 1, 8, 54, 384...
  20. Find Nth term of the series 1, 1, 2, 6, 24...
  21. Difference Between LinkedList and LinkedHashSet in Java
  22. Replace every element of the array by sum of all other elements
  23. Product of all prime nodes in a Doubly Linked List
  24. Convert a String to Integer Array in C/C++
  25. Sum of the nodes of a Singly Linked List
  26. Find count of common nodes in two Doubly Linked Lists
  27. Balance a string after removing extra brackets
  28. Delete all the nodes from the list which are less than K
  29. Convert List of Characters to String in Java
  30. Find other two sides and angles of a right angle triangle
  31. Delete linked list nodes which have a greater value on left side
  32. Delete all the nodes from a doubly linked list that are smaller than a given value
  33. Sum of all nodes in a doubly linked list divisible by a given number K
  34. Code valid in both C and C++ but produce different output
  35. Program to Convert List to Map in Java
  36. Delete all the nodes from the list which are divisible by any given number K
  37. Replace even nodes of a doubly linked list with the elements of array
  38. Delete linked list nodes which have a Lesser Value on Left Side
  39. Maximum element in min heap
  40. Sum of the nodes of a Circular Linked List
  41. Delete all the even nodes of a Circular Linked List
  42. Print all even nodes of Binary Search Tree
  43. Delete all Prime Nodes from a Circular Singly Linked List
  44. Print Sum and Product of all Non-Leaf nodes in Binary Tree
  45. Find normal at a given point on the curve
  46. Find first and last element of ArrayList in java
  47. Remove all elements from the ArrayList in Java
  48. Remove repeated elements from ArrayList in Java
  49. Find Tangent at a given point on the curve
  50. Convert String to Double in Java
  51. Program to Convert a Vector to List in Java
  52. Min and Max in a List in Java
  53. Convert Double to Integer in Java
  54. Find common elements in two ArrayLists in Java
  55. Convert an ArrayList of String to a String array in Java
  56. Difference between HashMap and HashSetv
  57. Find two non-overlapping pairs having equal sum in an Array
  58. Difference between length of Array and size of ArrayList in Java
  59. Print all nodes between two given levels in Binary Tree
  60. Method within method in java
  61. Split a list into two halves in Java
  62. Get name of current method being executed in Java
  63. How do Dynamic arrays work?
  64. Differences between wait() and join() methods in Java
  65. Count number of a class objects created in Java
  66. Get first and last elements from ArrayList in Java
  67. Difference between ArrayList and HashSet in Java
  68. What is the difference between field, variable, attribute, and property in Java
  69. LinkedHashMap and LinkedHashSet in Java
  70. Calculate volume and surface area of Torus
  71. Format Specifiers in Java
  72. Remove all occurrences of an element from Array in Java
  73. Future and FutureTask in java
  74. Find minimum and maximum elements in singly Circular Linked List
  75. BlockingQueue Interface in Java
  76. Difference Between Daemon Threads and User Threads In Java
  77. Deletion at different positions in a Circular Linked List
  78. Delete all odd or even positioned nodes from Circular Linked List
  79. Array implementation of queue (Simple)
  80. Sum and Product of the nodes of a Circular Singly Linked List which are divisible by K
  81. Difference between a Static Queue and a Singly Linked List
  82. Generate random String of given size in Java
  83. Print all pairs in an unsorted array with equal sum
  84. ArrayList vs. HashMap in Java
  85. How to select multiple columns in a pandas dataframe
  86. Non-generic Vs Generic Collection in Java
  87. DelayQueue class in Java with Example
  88. Different ways to sort an array in descending order in C#
  89. Randomly select items from a List in Java
  90. Find smallest and largest element from square matrix diagonals
  91. Reset Index in Pandas Dataframe
  92. Blocks in PL/SQL
  93. Get unique values from a column in Pandas DataFrame
  94. How to drop one or multiple columns in Pandas Dataframe
  95. valarray atan2() function in C++
  96. Difference and similarities between HashSet, LinkedHashSet and TreeSet in Java
  97. Maximum sum of cocktail glass in a 2D matrix
  98. Queries to find the first non-repeating character in the sub-string of a string
  99. Check whether array has all identical elements using Arrays.asList() and HashSet in Java
  100. Program to calculate the area of Kite
You may use GeeksforGeeks CONTRIBUTE portal to help other geeks. For more info, please refer this.

  1. Write a program to reverse digits of a number
  2. Program for n'th node from the end of a Linked List
  3. Write a function to delete a Linked List
  4. Reverse a linked list
  5. Function to check if a singly linked list is palindrome
  6. k largest(or smallest) elements in an array | added Min Heap method
  7. Compute the integer absolute value (abs) without branching
  8. Block swap algorithm for array rotation
  9. Print reverse of a Linked List without actually reversing
  10. Count Inversions in an array | Set 1 (Using Merge Sort)
  11. Maximum and minimum of an array using minimum number of comparisons
  12. Find whether a given number is a power of 4 or not
  13. Maximum width of a binary tree
  14. Identical Linked Lists
  15. Find the two repeating elements in a given array
  16. Evaluation order of operands
  17. Detect and Remove Loop in a Linked List
  18. Check if a binary tree is subtree of another binary tree | Set 1
  19. Add two numbers represented by linked lists | Set 1
  20. Delete a given node in Linked List under given constraints
  21. Sorted Linked List to Balanced BST
  22. Check whether two strings are anagram of each other
  23. Check whether a given string is an interleaving of two other given strings
  24. Pattern Searching | Set 6 (Efficient Construction of Finite Automata)
  25. Hamiltonian Cycle | Backtracking-6
  26. Longest Palindromic Subsequence | DP-12
  27. Find a triplet from three linked lists with sum equal to a given number
  28. Find a pair with given sum in a Balanced BST
  29. Minimum insertions to form a palindrome | DP-28
  30. Longest Common Substring | DP-29
  31. Delete N nodes after M nodes of a linked list
  32. Print all possible paths from top left to bottom right of a mXn matrix
  33. Pairwise swap elements of a given linked list by changing links
  34. Find if two rectangles overlap
  35. Check if a given Binary Tree is height balanced like a Red-Black Tree
  36. Remove minimum elements from either side such that 2*min becomes more than max
  37. Program for nth Catalan Number
  38. Check if a binary tree is subtree of another binary tree | Set 2
  39. Print squares of first n natural numbers without using *, / and -
  40. Print all elements in sorted order from row and column wise sorted matrix
  41. Multiply two polynomials
  42. How to check if two given sets are disjoint?
  43. K'th Smallest/Largest Element in Unsorted Array | Set 3 (Worst Case Linear Time)
  44. Given a linked list of line segments, remove middle points
  45. Longest Even Length Substring such that Sum of First and Second Half is same
  46. Print all paths from a given source to a destination
  47. Greedy Algorithm for Egyptian Fraction
  48. Check whether a binary tree is a complete tree or not | Set 2 (Recursive Solution)
  49. Group multiple occurrence of array elements ordered by first occurrence
  50. Iterative Merge Sort
  51. Compute n! under modulo p
  52. Converting Decimal Number lying between 1 to 3999 to Roman Numerals
  53. Remove spaces from a given string
  54. Compute sum of digits in all numbers from 1 to n
  55. Count BST subtrees that lie in given range
  56. Converting a Real Number (between 0 and 1) to Binary String
  57. Count distinct elements in every window of size k
  58. Collect maximum points in a grid using two traversals
  59. Maximum Path Sum in a Binary Tree
  60. Count total number of N digit numbers such that the difference between sum of even and odd digits is 1
  61. Print string of odd length in 'X' format
  62. Lazy Propagation in Segment Tree
  63. Find minimum possible size of array with given rules for removing elements
  64. Count number of ways to partition a set into k subsets
  65. Compare two strings represented as linked lists
  66. Print cousins of a given node in Binary Tree
  67. Number of paths with exactly k coins
  68. Combinatorial Game Theory | Set 3 (Grundy Numbers/Nimbers and Mex)
  69. Clone a linked list with next and random pointer in O(1) space
  70. Find the smallest twins in given range
  71. Count number of ways to divide a number in 4 parts
  72. Print individual digits as words without using if or switch
  73. Euler's criterion (Check if square root under modulo p exists)
  74. Find Square Root under Modulo p | Set 1 (When p is in form of 4*i + 3)
  75. G-Fact 19 (Logical and Bitwise Not Operators on Boolean)
  76. Rearrange an array in maximum minimum form | Set 1
  77. Form minimum number from given sequence
  78. How to avoid overflow in modular multiplication?
  79. 1's and 2's complement of a Binary Number
  80. Number of Integral Points between Two Points
  81. Print leftmost and rightmost nodes of a Binary Tree
  82. Add 1 to a number represented as linked list
  83. Comparator Interface in Java with Examples
  84. Print root to leaf paths without using recursion
  85. Common elements in all rows of a given matrix
  86. Maximum product of a triplet (subsequnece of size 3) in array
  87. Find smallest range containing elements from k lists
  88. Find if string is K-Palindrome or not | Set 1
  89. Wildcard Pattern Matching
  90. Smallest Subarray with given GCD
  91. Number of ways to calculate a target number using only array elements
  92. Rearrange a string so that all same characters become atleast d distance away
  93. How to find Lexicographically previous permutation?
  94. Longest Common Prefix using Character by Character Matching
  95. Longest Common Prefix using Trie
  96. Implement a stack using single queue
  97. Palindrome Substring Queries
  98. Find if string is K-Palindrome or not | Set 2
  99. Print extreme nodes of each level of Binary Tree in alternate order
  100. Find all triplets in a sorted array that forms Geometric Progression
  101. Check if string follows order of characters defined by a pattern or not | Set 1
  102. Reverse an array in groups of given size | Set 2 (Variations of Set 1 )
  103. Find if an expression has duplicate parenthesis or not
  104. A Space Optimized DP solution for 0-1 Knapsack Problem
  105. Maximize value of (arr[i] - i) - (arr[j] - j) in an array
  106. Longest repeating and non-overlapping substring
  107. Pairs of complete strings in two sets of strings
  108. Connect Nodes at same Level (Level Order Traversal)
  109. Queries in a Matrix
  110. Count all pairs with given XOR
  111. Swap Nodes in Binary tree of every k'th level
  112. Count of distinct substrings of a string using Suffix Trie
  113. Check if there is a root to leaf path with given sequence
  114. Aliquot Sequence
  115. Sum of maximum elements of all subsets
  116. Count characters at same position as in English alphabet
  117. Maximum subsequence sum such that no three are consecutive
  118. Print matrix in diagonal pattern
  119. Maximum decimal value path in a binary matrix
  120. Sort even-placed elements in increasing and odd-placed in decreasing order
  121. Find the first natural number whose factorial is divisible by x
  122. Program to implement Collatz Conjecture
  123. Count natural numbers whose all permutation are greater than that number
  124. Rearrange an array to minimize sum of product of consecutive pair elements
  125. Find pair with greatest product in array
  126. Find a partition point in array
  127. Find pairs in array whose sums already exist in array
  128. K-th smallest element after removing some integers from natural numbers
  129. Queries on substring palindrome formation
  130. Primitive root of a prime number n modulo n
  131. Sum of matrix in which each element is absolute difference of its row and column numbers
  132. Friends Pairing Problem
  133. Minimum steps to reach target by a Knight | Set 1
  134. Count binary strings with k times appearing adjacent two set bits
  135. Implementation of Affine Cipher
  136. Program for FCFS Scheduling | Set 1
  137. Check if there exist two elements in an array whose sum is equal to the sum of rest of the array
  138. Check if reversing a sub array make the array sorted
  139. Maximize sum of N X N upper left sub-matrix from given 2N X 2N matrix
  140. Find all triplets with zero sum
  141. Print a matrix in alternate manner (left to right then right to left)
  142. Circular Singly Linked List | Insertion
  143. Largest subsequence having GCD greater than 1
  144. Number with maximum number of prime factors
  145. Ways to represent a number as a sum of 1's and 2's
  146. Make largest palindrome by changing at most K-digits
  147. Find largest word in dictionary by deleting some characters of given string
  148. Number Theory | Generators of finite cyclic group under addition
  149. Find longest sequence of 1's in binary representation with one flip
  150. Character replacement after removing duplicates from a string
  151. Lexicographically first palindromic string
  152. Minimum swaps to reach permuted array with at most 2 positions left swaps allowed
  153. Point Clipping Algorithm in Computer Graphics
  154. Convert decimal fraction to binary number
  155. Search, insert and delete in an unsorted array
  156. Search, insert and delete in a sorted array
  157. Find sum of non-repeating (distinct) elements in an array
  158. Number of substrings divisible by 6 in a string of integers
  159. Count half nodes in a Binary tree (Iterative and Recursive)
  160. Noble integers in an array (count of greater elements is equal to value)
  161. Find Duplicates of array using bit array
  162. Multiply large integers under large modulo
  163. Change a Binary Tree so that every node stores sum of all nodes in left subtree
  164. Check if characters of a given string can be rearranged to form a palindrome
  165. Lexicographically minimum string rotation | Set 1
  166. Find the largest three elements in an array
  167. Triangular Numbers
  168. Program to print Sum Triangle for a given array
  169. Check if two numbers are equal without using arithmetic and comparison operators
  170. Queue | Set 2 (Linked List Implementation)
  171. Search an element in a Linked List (Iterative and Recursive)
  172. Insertion Sort for Singly Linked List
  173. Delete last occurrence of an item from linked list
  174. Minimum number of Appends needed to make a string palindrome
  175. Move spaces to front of string in single traversal
  176. Binary representation of next number
  177. Sort an array of strings according to string lengths
  178. Binary representation of next greater number with same number of 1's and 0's
  179. Remove all occurrences of duplicates from a sorted Linked List
  180. k-th distinct (or non-repeating) element in an array.
  181. Count number of ways to jump to reach end
  182. Reverse an array without using subtract sign ‘-‘ anywhere in the code
  183. First element occurring k times in an array
  184. Partitioning a linked list around a given value and If we don't care about making the elements of the list "stable"
  185. Count subsets having distinct even numbers
  186. Smallest window that contains all characters of string itself
  187. Shortest Uncommon Subsequence
  188. Program to find Smallest and Largest Word in a String
  189. Program to remove vowels from a String
  190. Convert a given Binary tree to a tree that holds Logical AND property
  191. Sum of divisors of factorial of a number
  192. Check whether a given binary tree is perfect or not
  193. Find Index of 0 to be replaced with 1 to get longest continuous sequence of 1s in a binary array | Set-2
  194. Find uncommon characters of the two strings
  195. String containing first letter of every word in a given string with spaces
  196. URLify a given string (Replace spaces is %20)
  197. Maximizing Unique Pairs from two arrays
  198. Reverse vowels in a given string
  199. Program for quotient and remainder of big number
  200. Count pairs from two sorted arrays whose sum is equal to a given value x
  201. Painting Fence Algorithm
  202. Find Corners of Rectangle using mid points
  203. Print all internal nodes of a Binary tree
  204. Check if a string is Isogram or not
  205. Check if absolute difference of consecutive nodes is 1 in Linked List
  206. Check if an array represents Inorder of Binary Search tree or not
  207. Find the sum of last n nodes of the given Linked List
  208. Find two numbers from their sum and XOR
  209. Maximize matrix as per given condition
  210. Subarray Inversions
  211. Count quadruples from four sorted arrays whose sum is equal to a given value x
  212. Find k-th bit in a binary string created by repeated invert and append operations
  213. Lexicographically n-th permutation of a string
  214. Master Theorem For Subtract and Conquer Recurrences
  215. Count words that appear exactly two times in an array of words
  216. Find length of loop in linked list
  217. Find a string such that every character is lexicographically greater than its immediate next character
  218. Check if binary representation of a given number and its complement are anagram
  219. Reverse a Linked List according to its Size
  220. Construct a complete binary tree from given array in level order fashion
  221. Longest Prime Subarray after removing one element
  222. Find any one of the multiple repeating elements in read only array
  223. Minimum Index Sum for Common Elements of Two Lists
  224. Merging two unsorted arrays in sorted order
  225. Longest common substring in binary representation of two numbers
  226. Find the fractional (or n/k - th) node in linked list
  227. Largest number with the given set of N digits that is divisible by 2, 3 and 5
  228. Find modular node in a linked list
  229. Minimize cost of operation to equalize tower heights
  230. Shortest distance between two nodes in BST
  231. An interesting solution to get all prime numbers smaller than n
  232. Given two strings check which string makes a palindrome first
  233. Smallest element in an array that is repeated exactly 'k' times.
  234. A modified game of Nim
  235. Count subarrays with equal number of occurrences of two given elements
  236. Insertion in a Binary Tree in level order
  237. Longest Common Substring in an Array of Strings
  238. Insert node into the middle of the linked list
  239. Smallest element repeated exactly ‘k’ times (not limited to small range)
  240. Length of the smallest sub-string consisting of maximum distinct characters
  241. Remove three consecutive duplicates from string
  242. Interleave the first half of the queue with second half
  243. Find the n-th number whose binary representation is a palindrome
  244. Diameter of a Binary Tree in O(n) [A new method]
  245. Longest subsequence where every character appears at-least k times
  246. Count pairs in an array such that LCM(arr[i], arr[j]) > min(arr[i],arr[j])
  247. Program for SSTF disk scheduling algorithm
  248. Binary representation of previous number
  249. Operating System | Program for Next Fit algorithm in Memory Management
  250. Count number of digits after decimal on dividing a number
  251. Count unset bits of a number
  252. Array range queries over range queries
  253. DFS for a n-ary tree (acyclic graph) represented as adjacency list
  254. Maximize the binary matrix by filpping submatrix once
  255. Smallest number k such that the product of digits of k is equal to n
  256. Make middle node head in a linked list
  257. Sort string of characters
  258. Unique element in an array where all elements occur k times except one
  259. Count of alphabets having ASCII value less than and greater than k
  260. Largest number with one swap allowed
  261. Check if a string is suffix of another
  262. Sudo Placement[1.4] | BST Traversal
  263. Happy Numbers
  264. Sort a Rotated Sorted Array
  265. Unique cells in a binary matrix
  266. Lexicographically largest subsequence such that every character occurs at least k times
  267. Maximize value of (a[i]+i)*(a[j]+j) in an array
  268. Replace node with depth in a binary tree
  269. Generate permutations with only adjacent swaps allowed
  270. Common characters in n strings
  271. Simplify the directory path (Unix like)
  272. Check if the given array can represent Level Order Traversal of Binary Search Tree
  273. Minimum sum by choosing minimum of pairs from array
  274. Reverse a circular linked list
  275. Program to sort string in descending order
  276. Lexicographically smallest permutation with distinct elements using minimum replacements
  277. Smallest root of the equation x^2 + s(x)*x - n = 0, where s(x) is the sum of digits of root x.
  278. Distinct permutations of the string | Set 2
  279. Minimum number of elements to add to make median equals x
  280. Average numbers in array
  281. Count all 0s which are blocked by 1s in binary matrix
  282. Remove all characters other than alphabets from string
  283. Longest subarray not having more than K distinct elements
  284. Encoding a word into Pig Latin
  285. Largest number less than or equal to N in BST (Iterative Approach)
  286. Find if there is a rectangle in binary matrix with corners as 1
  287. Sort an array with swapping only with a special element is allowed
  288. Sorting using trivial hash function
  289. Maximum consecutive numbers present in an array
  290. Count sub-arrays which have elements less than or equal to X
  291. Maximum and Minimum value of a quadratic function
  292. Mirror of matrix across diagonal
  293. Count of operations to make a binary string"ab" free
  294. Find index of closing bracket for a given opening bracket in an expression
  295. Generate original array from an array that store the counts of greater elements on right
  296. Next word that does not contain a palindrome and has characters from first k
  297. Construct lexicographically smallest palindrome
  298. Print Longest Palindromic Subsequence
  299. Unset the last m bits
  300. Length of longest strict bitonic subsequence
  301. Minimum cost to construct a string
  302. Queries for maximum difference between prime numbers in given ranges
  303. Binary Tree (Array implementation)
  304. Find largest element from array without using conditional operator
  305. Largest divisible pairs subset
  306. Minimum cost to make Longest Common Subsequence of length k
  307. DFS traversal of a tree using recursion
  308. Form the largest palindromic number using atmost two swaps
  309. Count subarrays with equal number of 1's and 0's
  310. Minimum number of subsets with distinct elements
  311. Print first N Mosaic numbers
  312. Program for triangular patterns of alphabets
  313. Print Reverse a linked list using Stack
  314. Check if the given string is the same as its reflection in a mirror
  315. Minimum difference between groups of size two
  316. Minimum Cost to make two Numeric Strings Identical
  317. Insert a whole linked list into other at k-th position
  318. Find next right node of a given key | Set 2
  319. Palindromic Selfie Numbers
  320. Rank of all elements in an array
  321. Operating System | Banker's Algorithm : Print all the safe state (or safe sequences)
  322. Make a loop at k-th position in a linked list
  323. Delete a linked list using recursion
  324. Height of binary tree considering even level leaves only
  325. Check if both halves of the string have at least one different character
  326. Covert string X to an anagram of string Y with minimum replacements
  327. Find the largest node in Doubly linked list
  328. Reduce Hamming distance by swapping two characters
  329. Partitioning into two contiguous element subarrays with equal sums
  330. Count consonants in a string (Iterative and recursive methods)
  331. Program to find simple moving average
  332. Connell Sequence
  333. String from prefix and suffix of given two strings
  334. Tilt of Binary Tree
  335. Maximum distinct lowercase alphabets between two uppercase
  336. Alternate Odd and Even Nodes in a Singly Linked List
  337. Expression contains redundant bracket or not
  338. Maximum spiral sum in Binary Tree
  339. Leaf nodes from Preorder of a Binary Search Tree (Using Recursion)
  340. Consecutive sequenced numbers in a string
  341. Total numbers with no repeated digits in a range
  342. N Queen in O(n) space
  343. Remove all outgoing edges except edge with minimum weight
  344. Substrings starting with vowel and ending with consonants and vice versa
  345. Non-Repeating Element
  346. Insertion sort to sort even and odd positioned elements in different orders
  347. Program to copy the contents of one array into another in the reverse order
  348. Sorted merge in one array
  349. Program to check if matrix is singular or not
  350. Check given array of size n can represent BST of n levels or not
  351. Find middle of singly linked list Recursively
  352. Count ordered pairs of positive numbers such that their sum is S and XOR is K
  353. Reverse each word in a linked list node
  354. Find the only repetitive element between 1 to n-1
  355. Power Set in Lexicographic order
  356. Function to copy string (Iterative and Recursive)
  357. Sort an array containing two types of elements
  358. Check if two strings are permutation of each other
  359. Schedule jobs so that each server gets equal load
  360. Find one extra character in a string
  361. Check if item can be measured using a scale and some weights
  362. Lexicographically next greater string using same character set
  363. Array range queries for elements with frequency same as value
  364. Count substrings with each character occurring at most k times
  365. Generate a list of n consecutive composite numbers (An interesting method)
  366. Reverse Morris traversal using Threaded Binary Tree
  367. Check if it possible to partition in k subarrays with equal sum
  368. Check if linked list is sorted (Iterative and Recursive)
  369. Number of common base strings for two strings
  370. Find the Largest Cube formed by Deleting minimum Digits from a number
  371. Dynamic Programming | Wildcard Pattern Matching | Linear Time and Constant Space
  372. Find nth term of the Dragon Curve Sequence
  373. Hill Cipher
  374. Find maximum element of each row in a matrix
  375. Maximum product subset of an array
  376. Arithmetic Number
  377. Position of n among the numbers made of 2, 3, 5 & 7
  378. Program to display all alphabets from A to Z in uppercase and lowercase both
  379. Longest substring having K distinct vowels
  380. Number of ways to merge two arrays such retaining order
  381. Print reverse string after removing vowels
  382. Program to reverse a string (Iterative and Recursive)
  383. Check for balanced parentheses in an expression | O(1) space
  384. Minimum bit changes in Binary Circular array to reach a index
  385. Maximum adjacent difference in an array in its sorted form
  386. Count pairs with set bits sum equal to K
  387. Reverse String according to the number of words
  388. Maximum product quadruple (sub-sequence of size 4) in array
  389. Add n binary strings
  390. Subtract 1 without arithmetic operators
  391. Check whether the number formed by concatenating two numbers is a perfect square or not
  392. Longest subarray such that adjacent elements have at least one common digit | Set 1
  393. Print concentric rectangular pattern in a 2d matrix
  394. Design a stack to retrieve original elements and return the minimum element in O(1) time and O(1) space
  395. Multiset Equivalence Problem
  396. Sort the biotonic doubly linked list | Set-2
  397. Find n-th node in Preorder traversal of a Binary Tree
  398. Find a Symmetric matrix of order N that contain integers from 0 to N-1 and main diagonal should contain only 0's
  399. Find the closest element in Binary Search Tree | Space Efficient Method
  400. Find the number of operations required to make all array elements Equal
  401. Convert a Binary Tree such that every node stores the sum of all nodes in its right subtree
  402. Recursive program to generate power set
  403. Repeated Character Whose First Appearance is Leftmost
  404. Print all triplets with given sum
  405. Print all distinct circular strings of length M in lexicographical order
  406. Number of permutations such that sum of elements at odd index and even index are equal
  407. Degree of a Cycle Graph
  408. Minimum inverting factor in an array
  409. Minimum steps needed to cover a sequence of points on an infinite grid
  410. Make all numbers of an array equal
  411. Remove leading zeros from an array
  412. Remove edges connected to a node such that the three given nodes are in different trees
  413. Number of Larger Elements on right side in a string
  414. Print cousins of a given node in Binary Tree | Single Traversal
  415. Permutation of a string with maximum number of characters greater than its adjacent characters
  416. Reduce string to shortest length by deleting a pair of same adjacent characters
  417. Replace every element with the greatest element on its left side
  418. Check if concatenation of two strings is balanced or not
  419. Lexicographically smallest string formed by appending a character from the first K characters of a given string
  420. Sudo Placement[1.3] | Stack Design
  421. Number of Counterclockwise shifts to make a string palindrome
  422. Delete all the nodes from the doubly linked list that are greater than a given value
  423. First non-repeating character using one traversal of string | Set 2
  424. Sum of all maximum frequency elements in Matrix
  425. Replace every character of string by character whose ASCII value is K times more than it
  426. Sudo Placement[1.5] | Wolfish
  427. Sorting without comparison of elements
  428. Sum of all prime divisors of all the numbers in range L-R
  429. Number of elements smaller than root using preorder traversal of a BST
  430. Find indices of all occurrence of one string in other
  431. Possible number of Rectangle and Squares with the given set of elements
  432. Count pairs with Bitwise XOR as ODD number
  433. Saddleback Search Algorithm in a 2D array
  434. Flatten a binary tree into linked list | Set-2
  435. Delete array element in given index range [L - R]
  436. Number of integral solutions for equation x = b*(sumofdigits(x)^a)+c
  437. Sum of all elements repeating 'k' times in an array
  438. Total sum except adjacent of a given node in a Binary Tree
  439. Counting frequencies of array elements
  440. Bubble Sort On Doubly Linked List
  441. Split array to three subarrays such that sum of first and third subarray is equal and maximum
  442. Difference between fundamental data types and derived data types
  443. Minimum multiplications with {2, 3, 7} to make two numbers equal
  444. Kruskal's Algorithm (Simple Implementation for Adjacency Matrix)
  445. Minimum number of changes required to make the given array an AP
  446. Printing frequency of each character just after its consecutive occurrences
  447. Balanced expressions such that given positions have opening brackets | Set 2
  448. Minimum element in a max heap
  449. Check if Queue Elements are pairwise consecutive
  450. Modulo power for large numbers represented as strings
  451. Program to find GCD or HCF of two numbers using Middle School Procedure
  452. Check if the first and last digit of the smallest number forms a prime
  453. Sort first k values in ascending order and remaining n-k values in descending order
  454. Find kth node from Middle towards Head of a Linked List
  455. Convert an Array to a Circular Doubly Linked List
  456. Find Nth term of series 1, 4, 15, 72, 420...
  457. Recursive Approach to find nth node from the end in the linked list
  458. Longest subarray having maximum sum
  459. Reverse a doubly circular linked list
  460. LIFO (Last-In-First-Out) approach in Programming
  461. Remove duplicates from a string in O(1) extra space
  462. Sum of the nodes of a Singly Linked List
  463. Check if a number is divisible by 41 or not
  464. Count elements that are divisible by at-least one element in another array
  465. Rat in a Maze | Backtracking using Stack
  466. Minimum operation require to make first and last character same
  467. Find Nth term (A matrix exponentiation example)
  468. Generating subarrays using recursion
  469. Recursively Reversing a linked list (A simple implementation)
  470. Find a palindromic string B such that given String A is a subsequense of B
  471. Check if given string can be formed by two other strings or their permutations
  472. Find any pair with given GCD and LCM
  473. Minimum number of palindromes required to express N as a sum | Set 2
  474. Count the number of ways to traverse a Matrix
  475. Count numbers (smaller than or equal to N) with given digit sum
  476. Delete all the nodes from a doubly linked list that are smaller than a given value
  477. Maximum and Minimum element of a linked list which is divisible by a given number k
  478. Find number of magical pairs of string of length L
  479. Check if Queue Elements are pairwise consecutive | Set-2
  480. Remove a given word from a String
  481. Ways to write N as sum of two or more positive integers | Set-2
  482. Replace even nodes of a doubly linked list with the elements of array
  483. Print Doubly Linked list in Reverse Order
  484. Delete all Prime Nodes from a Doubly Linked List
  485. Delete all nodes from the doubly linked list which are divisible by K
  486. Number of balanced bracket subsequence of length 2 and 4
  487. Replace minimal number of characters to make all characters pair wise distinct
  488. Find a peak element in Linked List
  489. Program to print the Zigzag pattern
  490. Find the largest good number in the divisors of given number N
  491. Check if there is any common character in two given strings
  492. How to access elements of a Square Matrix
  493. Meta Binary Search | One-Sided Binary Search
  494. Product of all nodes in a doubly linked list divisible by a given number K
  495. Check if it is possible to return to the starting position after moving in the given directions
  496. Find Sum of pair from two arrays with maximum sum
  497. Product of the nodes of a Singly Linked List
  498. Check whether it is possible to join two points given on circle such that distance between them is k
  499. Maximize the number of subarrays with XOR as zero
  500. Pair with given sum in matrix
  501. Check if a pair with given absolute difference exists in a Matrix
  502. Find the sum of all highest occurring elements in an Array
  503. Sum of all minimum occurring elements in an Array
  504. Sum of squares of Fibonacci numbers
  505. Remove BST Keys in a given Range
  506. Ulam Number Sequence
  507. Sum of all prime numbers in an Array
  508. Find pairs with given product in a sorted Doubly Linked List
  509. Check if there exists any sub-sequence in a string which is not palindrome
  510. Check if suffix and prefix of a string are palindromes
  511. Program to Print Mirrored Hollow Parallelogram
  512. Sum of the alternate nodes of linked list
  513. Largest element in the array that is repeated exactly k times
  514. Sum of Fibonacci numbers at even indexes upto N terms
  515. Check if a pair with given product exists in Linked list
  516. Find the node with maximum value in a Binary Search Tree
  517. Sort prime numbers of an array in descending order
  518. How to convert Vector to array in Java
  519. Search in a sorted 2D matrix (Stored in row major order)
  520. Rearrange all elements of array which are multiples of x in increasing order
  521. Maximum no. of contiguous Prime Numbers in an array
  522. Remove characters from string that appears strictly less than K times
  523. Check if any permutation of N equals any power of K
  524. Check if it is possible to rearrange a binary string with alternate 0s and 1s
  525. Check if there is any pair in a given range with GCD is divisible by k
  526. Get K-th letter of the decoded string formed by repeating substrings
  527. Check if a string contains a palindromic sub-string of even length
  528. Remove elements from the array which appear more than k times
  529. Replace every elements in the array by its frequency in the array
  530. Find the foot of perpendicular of a point in a 3 D plane
  531. Remove elements from the array whose frequency lies in the range [l, r]
  532. Find number of cavities in a matrix
  533. Immediate smallest number after re-arranging the digits of a given number
  534. Replace every array element by sum of previous and next
  535. String matching with * (that matches with any) in any of the two strings
  536. Assign other value to a variable from two possible values
  537. Minimize Cost with Replacement with other allowed
  538. Replace consonants with next immediate consonants alphabetically in a String
  539. Array elements with prime frequencies
  540. Sum and Product of all the nodes which are less than K in the linked list
  541. XOR of all Prime numbers in an Array
  542. Check whether it is possible to make both arrays equal by modifying a single element
  543. Number of words in a camelcase sequence
  544. Check whether all the rotations of a given number is greater than or equal to the given number or not
  545. Check whether product of digits at even places of a number is divisible by K
  546. Shortest distance to every other character from given character
  547. XOR of Prime Frequencies of Characters in a String
  548. Longest subarray with elements having equal modulo K
  549. N digit numbers divisible by 5 formed from the M digits
  550. Replace every element with the smallest element on its left side
  551. Replace each element by the difference of the total size of the array and frequency of that element
  552. Check if the Xor of the frequency of all digits of a number N is zero or not
  553. Magical Pattern
  554. Minimum number of elements to be replaced to make the given array a Fibonacci Sequence
  555. Program to print hollow Triangle pattern
  556. Find the count of palindromic sub-string of a string in its sorted form
  557. Check whether a given binary tree is skewed binary tree or not?
  558. Minimum swaps to group similar characters side by side?
  559. Count the number of words having sum of ASCII values less than and greater than k
  560. XOR of all elements of array with set bits equal to K
  561. Count number of bits changed after adding 1 to given N
  562. Find the value of f(n) / f(r) * f(n-r)
  563. Infix to Postfix using different Precedence Values for In-Stack and Out-Stack
  564. Maximum litres of water that can be bought with N Rupees
  565. Find the player who rearranges the characters to get a palindrome string first
  566. Check whether the frequencies of all the characters in a string are prime or not
  567. Program to remove consonants from a String
  568. Double ended priority queue
  569. Check if two nodes are in same subtree of the root node
  570. Minimum number of characters to be replaced to make a given string Palindrome
  571. Generate a sequence with the given operations
  572. Check if the given push and pop sequences of Stack is valid or not
  573. Sort perfect squares in an array at their relative positions
  574. Number of ways to reach the end of matrix with non-zero AND value
  575. Program to convert the diagonal elements of the matrix to 0
  576. Find minimum steps required to reach the end of a matrix | Set - 1
  577. Sum of elements whose square root is present in the array
  578. Reverse middle words of a string
  579. Check if the given decimal number has 0 and 1 digits only
  580. Program to print the given H Pattern
  581. Update adjacent nodes if the current node is zero in a Singly Linked List
  582. Check if moves in a stack or queue are possible or not
  583. Recursive program to print all subsets with given sum
  584. Add index to characters and reverse the string
  585. Count of Numbers in a Range where digit d occurs exactly K times
  586. Difference between Recursion and Iteration
  587. Buy minimum items without change and given coins
  588. Convert a String into a square matrix grid of characters
  589. Check if a number is perfect square without finding square root
  590. Represent n as the sum of exactly k powers of two | Set 2
  591. Shortest root to leaf path sum equal to a given number
  592. Find probability that a player wins when probabilities of hitting the target are given
  593. Number of subarrays have bitwise OR >= K
  594. Count of pairs violating BST property
  595. Smallest multiple of 3 which consists of three given non-zero digits
  596. Largest right circular cylinder that can be inscribed within a cone which is in turn inscribed within a cube
  597. Count distinct elements in an array
  598. Check if a string can be repeated to make another string
  599. Check whether the given character is in upper case, lower case or non alphabetic character
  600. Find safe cells in a matrix
  601. Find the Side of the smallest Square that can contain given 4 Big Squares
  602. Check if a number can be represented as a sum of 2 triangular numbers
  603. Minimum replacements to make adjacent characters unequal in a ternary string
  604. Closest sum partition (into two subsets) of numbers from 1 to n
  605. Form lexicographically smallest string with minimum replacements having equal number of 0s, 1s and 2s
  606. Number of sub-strings that contain the given character exactly k times
  607. Lexicographically largest sub-sequence of the given string
  608. Number of ways to choose an integer such that there are exactly K elements greater than it in the given array
  609. Sum of minimum elements of all possible sub-arrays of an array
  610. Find sub-matrix with the given sum
  611. Program to reverse a linked list using Stack
  612. Print Leaf Nodes at a given Level
  613. DFA for accepting the language L = {an bm | n+m=odd}
  614. Find a positive number M such that gcd(N^M, N&M) is maximum
  615. Given two binary strings perform operation until B > 0 and print the result
  616. Smallest Special Prime which is greater than or equal to a given number
  617. Split the array into odd number of segments of odd lengths
  618. Maximum Bitwise AND pair from given range
  619. Sum of all Submatrices of a Given Matrix
  620. Count array elements that divide the sum of all other elements
  621. Find the maximum value permutation of a graph
  622. Find Nth positive number whose digital root is X
  623. Sum of bitwise AND of all submatrices
  624. Number of connected components in a 2-D matrix of strings
  625. Longest subsequence such that adjacent elements have at least one common digit
  626. Minimum changes required to make a Catalan Sequence
  627. Two equal sum segment range queries
  628. Count of all even numbers in the range [L, R] whose sum of digits is divisible by 3
  629. Sum of numbers from 1 to N which are in Lucas Sequence
  630. Bitwise OR of N binary strings
  631. Minimize sum of adjacent difference with removal of one element from array
  632. Group consecutive characters of same type in a string
  633. Probability of A winning the match when individual probabilities of hitting the target given
  634. Minimum number of replacements to make the binary string alternating | Set 2
  635. Longest double string from a Palindrome
  636. Ways to form a group from three groups with given constraints
  637. Minimum number of bracket reversals needed to make an expression balanced | Set - 2
  638. Sum of the series (1*2) + (2*3) + (3*4) + ...... upto n terms
  639. Numbers that are not divisible by any number in the range [2, 10]
  640. Find the K-th minimum element from an array concatenated M times
  641. Maximum number that can be display on Seven Segment Display using N segments
  642. Program to calculate the value of nPr
  643. Check if the given array is mirror-inverse
  644. Minimum steps to make all the elements of the array divisible by 4
  645. Character whose frequency is equal to the sum of frequencies of other characters of the given string
  646. Find the side of the squares which are inclined diagonally and lined in a row
  647. Addition of two numbers without propagating Carry
  648. Find the sum of all Truncatable primes below N
  649. Minimum cuts required to convert a palindromic string to a different palindromic string
  650. Find maximum N such that the sum of square of first N natural numbers is not more than X
  651. Generate array with minimum sum which can be deleted in P steps
  652. Check if matrix can be converted to another matrix by transposing square sub-matrices
  653. Minimum changes required such that the string satisfies the given condition
  654. Find if the given number is present in the infinite sequence or not
  655. Find the number of good permutations
  656. Check if the given array can be reduced to zeros with the given operation performed given number of times
  657. Minimum length of square to contain at least half of the given Coordinates
  658. Count integers in a range which are divisible by their euler totient value
  659. Number of ways to make binary string of length N such that 0s always occur together in groups of size K
  660. Count sub-arrays whose product is divisible by k
  661. Find foot of perpendicular from a point in 2 D plane to a Line
  662. Find a pair from the given array with maximum nCr value
  663. Minimum steps to delete a string by deleting substring comprising of same characters
  664. Find a distinct pair (x, y) in given range such that x divides y
  665. Find the number of ways to divide number into four parts such that a = c and b = d
  666. Find 2^(2^A) % B
  667. Check if the given binary tree has a sub-tree with equal no of 1's and 0's | Set 2
  668. Maximize the value of the given expression
  669. Programs for printing pyramid patterns using recursion
  670. Sum of Fibonacci Numbers in a range
  671. Minimize the cost to split a number
  672. Count of sub-arrays whose elements can be re-arranged to form palindromes
  673. Partition the array into three equal sum segments
  674. Determine the numer of squares that line will pass through
  675. Find the good permutation of first N natural numbers
  676. Sum of degrees of all nodes of a undirected graph
  677. Find the hypotenuse of a right angled triangle with given two sides
  678. Sort ugly numbers in an array at their relative positions
  679. Reverse Clockwise spiral traversal of a binary tree
  680. Print all leaf nodes of a binary tree from right to left
  681. Count of sub-strings that do not contain all the characters from the set {'a', 'b', 'c'} at the same time
  682. Find the number of different numbers in the array after applying the given operation q times
  683. XOR of all the elements in the given range [L, R]
  684. Arrange given numbers to form the smallest number
  685. Find maximum in stack in O(1) without using additional stack
  686. Find the final radiations of each Radiated Stations
  687. Find number of edges that can be broken in a tree such that Bitwise OR of resulting two trees are equal
  688. Sum of nodes in a linked list which are greater than next node
  689. Count number of binary strings of length N having only 0's and 1's
  690. Length of the smallest number which is divisible by K and formed by using 1's only
  691. Find the number of binary strings of length N with at least 3 consecutive 1s
  692. Reduce the fraction to its lowest form
  693. Iterative selection sort for linked list
  694. Print path from root to all nodes in a Complete Binary Tree
  695. Insert N elements in a Linked List one after other at middle position
  696. Find the minimum number of operations required to make all array elements equal
  697. Sum of all distinct nodes in a linked list
  698. Sum of smaller elements of nodes in a linked list
  699. Count of quadruplets with given Sum
  700. Queries to answer the number of ones and zero to the left of given index
  701. Check if two strings are same ignoring their cases
  702. Find the sum of the number of divisors
  703. Travelling Salesman Problem implementation using BackTracking
  704. Queries to check if substring[L...R] is palindrome or not
  705. Count pairs of non-overlapping palindromic sub-strings of the given string
  706. Given a string and an integer k, find the kth sub-string when all the sub-strings are sorted according to the given condition
  707. Check whether the given string is a valid identifier
  708. Find the nth term of the given series
  709. Find the sum of leafs at maximum level
  710. Queries to update a given index and find gcd in range
  711. Remove all occurrences of any element for maximum array sum
  712. Highest power of a number that divides other number
  713. Maximum elements which can be crossed using given units of a and b
  714. Sum of the series 1, 2, 4, 3, 5, 7, 9, 6, 8, 10, 11, 13.. till N-th term
  715. Check if given two straight lines are identical or not
  716. Find sum of factorials in an array
  717. Count of quadruplets with given Sum | Set 2
  718. Find the Diameter or Longest chord of a Circle
  719. Determine the position of the third person on regular N sided polygon
  720. Length of the chord of the circle whose radius and the angle subtended at the center by the chord is given
  721. Reorder the position of the words in alphabetical order
  722. Given two arrays count all pairs whose sum is an odd number
  723. Print steps to make a number in form of 2^X - 1
  724. Length of the direct common tangent between two externally touching circles
  725. Maximize the given number by replacing a segment of digits with the alternate digits given
  726. Count unique numbers that can be generated from N by adding one and removing trailing zeros
  727. Find element with the maximum set bits in an array
  728. Minimum number of cubes whose sum equals to given number N
  729. Generate an array of K elements such that sum of elements is N and the condition a[i] < a[i+1] <= 2*a[i] is met | Set 2
  730. Calculate score for the given binary string
  731. Count number of 1s in the array after N moves
  732. Area of plot remaining at the end
  733. Minimum increments to convert to an array of consecutive integers
  734. Minimum deletions required such that any number X will occur exactly X times
  735. Count number of subsets whose median is also present in the same subset
  736. Ratio of the distance between the centers of the circles and the point of intersection of two direct common tangents to the circles
  737. Minimum operations required to change the array such that |arr[i] - M| <= 1
  738. Maximum sum path in a matrix from top to bottom and back
  739. Minimum number of given operations required to reduce the array to 0 element
  740. Find prime number K in an array such that (A[i] % K) is maximum
  741. Create a sequence whose XOR of elements is y
  742. Count squares with odd side length in Chessboard
  743. Find minimum steps required to reach the end of a matrix | Set 2
  744. Minimize the number of steps required to reach the end of the array | Set 2
  745. Minimum steps required to reach the end of a matrix | Set 2
  746. Queries for bitwise AND in the index range [L, R] of the given array
  747. Remove elements to make array satisfy arr[ i+1] < arr[i] for each valid i
  748. Program to find the number of men initially
  749. Count the nodes of the given tree whose weight has X as a factor
  750. Maximum Sum Subsequence of length k
  751. Change one element in the given array to make it an Arithmetic Progression
  752. Count number of ways to divide an array into two halves with same sum
  753. Check if each element of the given array is the product of exactly K prime numbers
  754. Number of ways to divide an array into K equal sum sub-arrays
  755. Count duplicates in a given linked list
  756. Print combinations of distinct numbers which add up to give sum N
  757. Find the largest possible k-multiple set
  758. Find the sum of the ascii values of characters which are present at prime positions
  759. Count of three non-overlapping sub-strings which on concatenation forms a palindrome
  760. Maximise array sum after taking non-overlapping sub-arrays of length K
  761. Sum of XOR of all sub-arrays of length K
  762. Count the number of digits of palindrome numbers in an array
  763. Count the maximum number of elements that can be selected from the array
  764. Find uncommon characters of the two strings | Set 2
  765. Minimum length subarray of 1s in a Binary Array
  766. Count number of distinct substrings of a given length
  767. Program to calculate angle on circumference subtended by the chord when the central angle subtended by the chord is given
  768. Longest prefix in a string with highest frequency
  769. Maximum sub-sequence sum such that indices of any two adjacent elements differs at least by 3
  770. Find the node with minimum value in a Binary Search Tree using recursion
  771. Queries for number of distinct elements from a given index till last index in an array
  772. Reverse the Sentence using Stack
  773. Minimum time required to rot all oranges | Dynamic Programming
  774. Rearrange characters in a string such that no two adjacent are same using hashing
  775. Kth smallest element in the array using constant space when array can't be modified
  776. Check whether it is possible to convert A into B
  777. Check whether str1 can be converted to str2 with the given operations
  778. Number of elements from the array which are reachable after performing given operations on D
  779. Maximum previous and next element product
  780. Find the minimum number of elements that should be removed to make an array good
  781. Find XOR of numbers from the range [L, R]
  782. Construct a DFA which accept the language L = {w | w ∈ {a,b}* and Na(w) mod 3 = Nb (w) mod 3}
  783. Construct a DFA which accept the language L = {anbm | n > =1, (m) mod 3 = 1}
  784. Find two vertices of an isosceles triangle in which there is rectangle with opposite corners (0, 0) and (X, Y)
  785. Minimum number of adjacent swaps to convert a string into its given anagram
  786. Probability of getting more heads than tails when N biased coins are tossed
  787. Coin Change | BFS Approach
  788. Minimum number of steps to convert a given matrix into Upper Hessenberg matrix
  789. Program to calculate the area of Kite
  790. Sum of Semi-Prime Numbers less than or equal to N
  791. Nodes from given two BSTs with sum equal to X
  792. Partiton the string in two parts such that both parts have at least k different characters
  793. Find the position of the given row in a 2-D array
  794. Unbounded Fractional Knapsack
  795. Find Leftmost and Rightmost node of BST from its given preorder traversal
  796. Count of non-overlapping sub-strings "101" and "010" in the given binary string
  797. Splitting starting N nodes into new Circular Linked List while preserving the old nodes