1. Circular Matrix (Construct a matrix with numbers 1 to m*n in spiral way)
  2. Number of occurrences of 2 as a digit in numbers from 0 to n
  3. Stack | Set 3 (Reverse a string using stack)
  4. Convert characters of a string to opposite case
  5. K-th Element of Two Sorted Arrays
  6. Ropes Data Structure (Fast String Concatenation)
  7. Maximum sum in a 2 x n grid such that no two elements are adjacent
  8. Check whether the length of given linked list is Even or Odd
  9. Find uncommon characters of the two strings
  10. String containing first letter of every word in a given string with spaces
  11. Ways of transforming one string to other by removing 0 or more characters
  12. Largest even number possible by using one swap operation in given number
  13. Lexicographically smallest permutation of {1, .. n} such that no. and position do not match
  14. Smallest number k such that the product of digits of k is equal to n
  15. Longest Repeated Subsequence
  16. Mean of range in array
  17. Programming puzzle (Assign value without any control statement)
  18. Modify a bit at a given position
  19. Average numbers in array
  20. Even-odd turn game with two integers
  21. Make alphabets using the elements of an array
  22. Replace a character c1 with c2 and c2 with c1 in a string S
  23. Program to print right and left arrow patterns
  24. Rearrange an array such that arr[i] = i
  25. Aspiring Number
  26. Find total number of distinct years from a string
  27. Maximum Possible Product in Array after performing given Operations
  28. Count pairs with Bitwise XOR as EVEN number
  29. First X vowels from a string
  30. Greatest divisor which divides all natural number in range [L, R]