Few Other Resources:
https://leetcode.com/discuss/general-discussion/665604/Important-and-Useful-links-from-all-over-the-LeetCode https://takeuforward.org/strivers-a2z-dsa-course/strivers-a2z-dsa-course-sheet-2
Top 50 Hard Questions from ChatGPT
Arrays & Strings:
Longest Substring Without Repeating Characters (Medium) Product of Array Except Self (Medium) Longest Palindromic Substring (Medium) Trapping Rain Water (Hard) Longest Consecutive Sequence (Hard) Substring with Concatenation of All Words (Hard) Median of Two Sorted Arrays (Hard) Sliding Window Maximum (Hard) Maximum Product Subarray (Medium) Longest Increasing Path in a Matrix (Hard)
Linked Lists:
Add Two Numbers (Medium) LRU Cache (Medium) Merge K Sorted Lists (Hard) Reverse Nodes in k-Group (Hard) Copy List with Random Pointer (Medium)
Trees & Graphs:
Binary Tree Maximum Path Sum (Hard) Serialize and Deserialize Binary Tree (Hard) Binary Search Tree Iterator (Medium) Kth Smallest Element in a BST (Medium) Number of Islands (Medium) Word Ladder (Hard) Course Schedule II (Medium) Alien Dictionary (Hard) Graph Valid Tree (Medium) Redundant Connection (Medium)
Dynamic Programming:
Longest Increasing Subsequence (Medium) House Robber III (Medium) Decode Ways (Medium) Unique Paths II (Medium) Longest Palindromic Subsequence (Medium) Word Break II (Hard) Edit Distance (Hard) Burst Balloons (Hard) Maximum Profit in Job Scheduling (Hard) Wild Card Matching (Hard)
Backtracking:
Permutations II (Medium) Combination Sum II (Medium) Word Search II (Hard) Palindrome Partitioning (Medium) N-Queens II (Hard) Sudoku Solver (Hard) Remove Invalid Parentheses (Hard) Restore IP Addresses (Medium) Advanced Data Structures: Implement Trie (Prefix Tree) (Medium) Design Search Autocomplete System (Hard) Design In-Memory File System (Hard) Design Search Autocomplete System (Hard) LFU Cache (Hard)
Math & Miscellaneous:
Basic Calculator (Hard) First Missing Positive (Hard)