Leetcode problems. Preparing for technical interviews

1. Challenges for New Users
   • 13. Roman to Integer
   • 234. Palindrome Linked List
   • 383. Ransom Note
   • 412. Fizz Buzz
   • 876. Middle of the Linked List
   • 1337. The K Weakest Rows in a Matrix
   • 1342. Number of Steps to Reduce a Number to Zero
   • 1672. Richest Customer Wealth
2. LeetCode 75
   • Day 1. Prefix Sum
     • 1480. Running Sum of 1d Array
     • 724. Find Pivot Index
   • Day 2. String
     • 205. Isomorphic Strings
     • 392. Is Subsequence
   • Day 3. Linked List
     • 21. Merge Two Sorted Lists
     • 206. Reverse Linked List
   • Day 4. Linked List
     • 876. Middle of the Linked List
     • 142. Linked List Cycle II
   • Day 5. Greedy
     • 121. Best Time to Buy and Sell Stock
     • 409. Longest Palindrome
   • Day 6. Tree
     • 589. N-ary Tree Preorder Traversal
     • 102. Binary Tree Level Order Traversal
   • Day 7. Binary Search
     • 704. Binary Search
     • 278. First Bad Version
   • Day 8. Binary Search Tree
     • 98. Validate Binary Search Tree
     • 235. Lowest Common Ancestor of a Binary Search Tree
   • Day 9. Graph/BFS/DFS
     • 733. Flood Fill
     • 200. Number of Islands