Problem-Solving Favorites

This is a list of my favorite coding problems from platforms like LeetCode and HackerRank, along with their corresponding solutions.

List of Problems

1. Contains Duplicate

   • Problem: Check if an array contains any duplicates.
   • Platform: LeetCode

2. Two Sum

   • Problem: Find two numbers in an array that add up to a specific target.
   • Platform: LeetCode

3. Roman Numbers to Integers

   • Problem: Convert Roman numerals to integers.
   • Platform: Custom

4. isPalindrome (String)

   • Problem: Check if a string is a palindrome.
   • Platform: Custom

5. isPalindrome (int)

   • Problem: Determine if an integer is a palindrome.
   • Platform: Custom

6. Sorted Squared Array

   • Problem: Square the elements of a sorted array while keeping them sorted.
   • Platform: Custom

7. First Non-Repeating Character

   • Problem: Find the first non-repeating character in a string.
   • Platform: LeetCode

8. isValid Parenthesis

   • Problem: Check if a given string of parentheses is valid.
   • Platform: LeetCode

9. Min Add to Make Parenthesis Valid

   • Problem: Find the minimum number of parentheses needed to make a string valid.
   • Platform: LeetCode

10. Find Peak in Mountain Array

    • Problem: Find the peak element in an array that represents a mountain.
    • Platform: LeetCode

11. Longest Common Subsequence

    • Problem: Find the length of the longest common subsequence between two strings.
    • Platform: HackerRank

12. Length of Longest Common Subsequence

    • Problem: Find the length of the longest common subsequence in an array of strings.
    • Platform: Custom

13. Search Suggestion System

    • Problem: Implement a search suggestion system based on user input.
    • Platform: LeetCode

14. Common Number in Three Arrays

    • Problem: Find a common number that exists in three arrays.
    • Platform: Custom

15. Minimum Number of Coins

    • Problem: Determine the minimum number of coins needed to make a specific amount.
    • Platform: Custom

16. Replace with Right Max

    • Problem: Replace each element in an array with the rightmost element greater than the current element.
    • Platform: Custom

17. Tic Tac Toe

    • Problem: Given a list of moves in a game of tic tac toe, return that state of the game.
    • If player A (the first player to move with X characters) wins, return ”A”.
    • If player B (the second player to move with O characters) wins, return ”B”.
    • Otherwise, if it’s a draw, return ”Draw” and if the game hasn’t finished, return ”Pending”.
    • Ex: Given the following moves…
    • moves = [[0,0],[1,0],[1,1],[2,0],[2,2]], return "A" (player A won with three Xs being connected along the diagonal).
    • Platform: Daily Byte

More to come 👍