1. https://www.geeksforgeeks.org/sum-of-natural-numbers-using-recursion/
  2. https://leetcode.com/problems/power-of-two/description/
  3. https://www.geeksforgeeks.org/problems/geek-onacci-number/0
  4. https://www.geeksforgeeks.org/first-uppercase-letter-in-a-string-iterative-and-recursive/
  5. https://leetcode.com/problems/power-of-three/
  6. https://leetcode.com/problems/power-of-four/
  7. https://www.geeksforgeeks.org/problems/check-if-an-array-is-sorted0701/1?itm_source=geeksforgeeks&itm_medium=article&itm_campaign=bottom_sticky_on_article
  8. https://www.geeksforgeeks.org/problems/recursively-remove-all-adjacent-duplicates0744/1?itm_source=geeksforgeeks&itm_medium=article&itm_campaign=bottom_sticky_on_article
  9. https://leetcode.com/problems/powx-n/description/
  10. https://www.geeksforgeeks.org/problems/n-digit-numbers-with-digits-in-increasing-order5903/1
  11. https://leetcode.com/problems/generate-parentheses/description/
  12. https://leetcode.com/problems/string-to-integer-atoi/submissions/884942399/
  13. https://www.geeksforgeeks.org/generate-binary-strings-without-consecutive-1s/?utm_source=youtube&utm_medium=collab_striver_ytdescription&utm_campaign=generate-binary-strings-without-consecutive-1s
  14. https://www.geeksforgeeks.org/problems/replace-all-0s-with-5/1?itm_source=geeksforgeeks&itm_medium=article&itm_campaign=bottom_sticky_on_article
  15. https://www.geeksforgeeks.org/print-even-and-odd-numbers-in-a-given-range-using-recursion/
  16. https://www.geeksforgeeks.org/find-all-the-possible-mappings-of-characters-in-a-sorted-order/
  17. https://www.geeksforgeeks.org/convert-a-string-to-an-integer-using-recursion/
  18. https://leetcode.com/problems/target-sum/description/
  19. https://leetcode.com/problems/subsets/
  20. https://leetcode.com/problems/subsets-ii/