Day 80: LeetCode 222 Count Complete Tree Nodes | O(log²n) Solution | Google | Top Interview 150

Day 79: LeetCode 173 Binary Search Tree Iterator | Inorder Traversal + Stack | Top Interview 150

Day 78: LeetCode 124 Binary Tree Maximum Path Sum | Postorder DFS + Recursion | Top Interview 150

Day 77: LeetCode 129 Sum Root to Leaf Numbers | DFS + Recursion | Google | Meta | Top Interview 150

Day 76: LeetCode 112 Path Sum | Iterative DFS + Two Stacks | Google | Meta | Top Interview 150

Day 75: LeetCode 114 Flatten Binary Tree | Reverse Preorder + Recursion | Google | Top Interview 150

Day 74: LeetCode 117 Populating Next Right Pointers II | O(1) Space | Google | Top Interview 150

Day 73: LeetCode 106 Construct Binary Tree | Inorder + Postorder | Google | Top Interview 150

Day 72: LeetCode 105 Construct Binary Tree | Recursion + HashMap | Google | Top Interview 150

DFS vs BFS Explained | Depth First Search vs Breadth First Search | DSA Patterns in Hinglish

Day 71: LeetCode 101 Symmetric Tree | Recursion + Mirror Comparison | Google | Top Interview 150

Day 70: LeetCode 226 Invert Binary Tree | BFS + Queue | Google | Meta | Amazon | Top Interview 150

Day 69: LeetCode 100 Same Tree | Level Order Traversal + Queue | Google | Meta | Top Interview 150

You’re Learning to Code the WRONG Way | Rahul Coder

Day 68: LeetCode 104 Maximum Depth of Binary Tree | DFS + Recursion | Google | Top Interview 150

Day 67: LeetCode 146 LRU Cache | HashMap + Doubly Linked List | O(1) Get & Put | Top Interview 150

Day 66: LeetCode 86 Partition List | Two Pointers + Dummy Nodes | Google | Meta | Top Interview 150

Day 65: LeetCode 61 Rotate List | Circular Linked List | Google | Meta | Amazon | Top Interview 150

Day 64: LeetCode 82 Remove Duplicates from Sorted List II | Meta | Two Pointers | Top Interview 150

Day 63: LeetCode 19 Remove Nth Node From End of List | Two Pointers | Google | Top Interview 150

Day 62: LeetCode 25 Reverse Nodes in k-Group | In-Place Reversal | Google | Meta | Top Interview 150

Day 61: LeetCode 92 Reverse Linked List II | In-Place Reversal | Google | Meta | Top Interview 150

Day 60: LeetCode 138 Copy List with Random Pointer | O(1) Space | Google | Meta | Top Interview 150

Day 59: LeetCode 21 Merge Two Sorted Lists | Two Pointers | Google | Meta | Top Interview 150

Day 58: LeetCode 2 Add Two Numbers | Linked List + Carry | Google | Meta | Top Interview 150

Day 57: LeetCode 141 Linked List Cycle | Fast & Slow Pointers | Google | Meta | Top Interview 150

Day 56: LeetCode 224 Basic Calculator | Stack Pattern | Google | Meta | Amazon | Top Interview 150

Day 55: LeetCode 150 Evaluate Reverse Polish Notation | Stack Pattern | Google | Top Interview 150

Day 54: LeetCode 155 Min Stack | Stack Design | Google | Meta | Microsoft | Top Interview 150

Day 53: LeetCode 71 Simplify Path | Stack Pattern | Leetcode 71 | Google | Meta | Top Interview 150

Day 52: LeetCode 20 Valid Parentheses | Stack Pattern | Meta | Google | Amazon | Top Interview 150

Day 51: LeetCode 57 Insert Interval | Intervals Pattern | Google | Meta | Amazon | Top Interview 150

Day 50: LeetCode 452 Minimum Number of Arrows to Burst Balloons | Google | Top Interview 150

Day 49: LeetCode 56 Merge Intervals | Sorting + Greedy | Meta | Interval Pattern | Top Interview 150

Day 48: LeetCode 228 Summary Ranges | Two Pointers | Google | Meta | Amazon | Top Interview 150

Day 47: LeetCode 128 Longest Consecutive Sequence | Hash Set | Google | Meta | Top Interview 150

Day 46: LeetCode 219 Contains Duplicate II | Hash Map + Sliding Window | Google | Top Interview 150

Day 45: LeetCode 202 Happy Number | Brute Force to Optimal (Hash Set) | Top Interview 150

Day 44: LeetCode 1 Two Sum | Brute Force to Optimal (Hash Map) | Google | Meta | Top Interview 150

Day 43: LeetCode 49 Group Anagrams | Brute Force to Optimal (Hash Map) | Top Interview 150

Day 42: LeetCode 242 Valid Anagram | Brute Force to Optimal (Hash Map) | Top Interview 150

Day 41: LeetCode 290 Word Pattern | Brute Force to Optimal (Two Hash Maps) | Top Interview 150

Day 40: LeetCode 205 Isomorphic Strings | Brute Force to Optimal (Two Hash Maps) | Top Interview 150

Day 39: LeetCode 383 Ransom Note | Hash Map Brute Force to Optimal (O(n)) | Top Interview 150

Day 38: LeetCode 289 Game of Life | Brute Force to Optimal (O(1) Space) | Top Interview 150

Day 37: LeetCode 73 Set Matrix Zeroes | Brute Force to Optimal (O(1) Space) | Top Interview 150

Day 36: LeetCode 48 Rotate Image | Brute Force to Optimal (Transpose + Reverse) | Top Interview 150

Day 35: LeetCode 54 Spiral Matrix | Brute Force to Optimal (Boundary Traversal) | Top Interview 150

Day 34: LeetCode 36 Valid Sudoku | Matrix | Hash Set | Google | Meta | Amazon | Top Interview 150

Day 33: LeetCode 76 Minimum Window Substring | Sliding Window + Hash Map| Top Interview 150

Day 32: LeetCode 30 Substring with Concatenation of All Words | Sliding Window | Top Interview 150

Day 31: LeetCode 3 Longest Substring Without Repeating Characters Sliding Window | Top Interview 150

Day 30: LeetCode 209 Minimum Size Subarray Sum | Optimal Sol (Sliding Window) | Top Interview 150

Sliding Window Pattern Explained | DSA for Beginners | LeetCode Sliding Window Tutorial in Hinglish

Day 29: LeetCode 15 3Sum | Brute Force to Optimal (Sorting + Two Pointers) | Top Interview 150

Day 28: LeetCode 11 Container With Most Water | Brute Force to Optimal | Google | Top Interview 150

Day 27: LeetCode 167 Two Sum II | Brute Force to Optimal (Two Pointers) | Google | Top Interview 150

Day 26: Text Justification | Brute Force to Optimal (Greedy) | Leetcode68 Google | Top Interview 150

Day 25: LeetCode 6 Zigzag Conversion | Brute Force to Optimal | GOOGLE | Top Interview 150

Day 24: LeetCode 151 Reverse Words in a String | Brute Force to Optimal | Top Interview 150