✅ Day 108 of 160 - GFG DSA Challenge.📊 Problem: Sliding Window Maximum.📌 Logic: Maintain a queue<int> to track current window; reset when max pops.⌛ Time Complexity: O(n*k) (worst case due to queue re-evaluation). #DSA #cpp #Queue #SlidingWindow #gfg2025 #gfg160dayschallenges

✅ Day 107 of 160 - GFG DSA Challenge.🧠 Problem: Decode a String.📌 Logic: Stack-based simulation to handle nested repetitions like 3[a2[c]].⌛ Time Complexity: O(n) — linear traversal and stack operations. #DSA #cpp #Stack #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 106 of 160 - GFG DSA Challenge.🧠 Problem: Evaluate Reverse Polish Notation (RPN).📌 Logic: Stack-based evaluation of postfix expression.⌛ Time Complexity: O(n). #DSA #cpp #Stack #Postfix #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 105 of 160 - GFG DSA Challenge.🧠 Problem: Implement a Stack with getMin() in O(1).📌 Logic: Maintain an auxiliary stack to track minimums alongside main stack.⌛ Time Complexity:.• push, pop, peek, getMin – all in O(1). #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 104of 160 - GFG DSA Challenge.🧠 Problem: Maximum of Minimums for Every Window Size.📌 Logic: Use stack to find NSL + NSR and store window lengths.⌛ Time Complexity: O(N). #DSA #cpp #Stack #SlidingWindow #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 103 of 160 - GFG DSA Challenge.🧠 Problem: Maximum Area Histogram.📌 Logic: Use a stack to find Nearest Smaller to Left & Right.⌛ Time Complexity: O(N). #DSA #cpp #Stack #MonotonicStack #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 102 of 160 - GFG DSA Challenge.🧠 Problem: Stock Span Problem.📌 Logic: Use a monotonic stack to find the span of each stock price.⌛ Time Complexity: O(N).Stack helps track the past to predict strength in the present . #cpp #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 101 of 160 - GFG DSA Challenge.🧠 Problem: Next Greater Element.📌 Logic: Traverse from right using a stack to find next greater element.⌛ Time Complexity: O(N). #DSA #cpp #Stack #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 100 of 160 - GFG DSA Challenge.🧠 Problem: Longest Valid Parentheses.📌 Logic: Use stack to track indices and calculate max length.⌛ Time Complexity: O(N).#DSA #cpp #Stack #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 99 of 160 - GFG DSA Challenge.🧠 Problem: Check for Balanced Parentheses.📌 Logic: Use Stack to match opening and closing brackets.⌛ Time Complexity: O(N). #DSA #cpp #Stack #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 98 of 160 - GFG DSA Challenge.🧠 Problem: Find Median in a Stream.📌 Logic: Two Heaps (Max-Heap & Min-Heap) to balance elements dynamically.⌛ Time Complexity: O(log N) per insertion. #DSA #cpp #Heap #Median #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 97 .of 160 - GFG DSA Challenge.🧠 Problem: Merge K Sorted Linked Lists.📌 Logic: Min Heap (Priority Queue) + Merge.⌛ Time Complexity: O(N log K), where N is total nodes and K is the number of lists. #DSA #cpp #LinkedList #Heap #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 96 of 160 - GFG DSA Challenge.🧠 Problem: K Closest Points to Origin.📌 Logic: Min Heap + Distance = x² + y².⌛ Time Complexity: O(N log N) — for pushing all N points into the heap and popping K times. #DSA #cpp #coding #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 95 of 160 - GFG DSA Challenge.🧠 Problem: K Largest Elements.📌 Logic: Max Heap using priority_queue.Heap + Top-K = Powerful combo for fast extraction! 🚀. #DSA #cpp #coding #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 94 of 160 - GFG DSA Challenge.🧠 Problem: Serialize and Deserialize a Binary Tree.📌 Logic: Preorder traversal + Sentinel (-1) for NULL. #DSA #cpp #coding #gfg2025 #gfgstreak2025 #gfg160dayschallenges

✅ Day 93 of 160 - GFG DSA Self-Paced.🔍 Problem Solved: Lowest Common Ancestor in BST.🌲 Logic: BST property + recursion.Efficiency meets elegance when recursion respects BST rules! 💡.#gfg160dayschallenge #DSA #GFG2025 #cpp #codingjourney #gfgstreak2025

✅ Day 92 of 160 - GFG 160 days challenges.🛠️ Problem Solved: Correct BST where two nodes are swapped.🔁 Approach: Inorder traversal + sort + restore.🔍 Understanding BST properties = 🔓 bug fixes! #GFGDSA #cpp #BinarySearchTree #DSA #gfg160dayschallenge #gfg2025 #gfgstreak2025

✅ Day 91of 160 - GFG DSA Self-Paced.🔥 Problem Solved: Find a pair with a given target sum in BST.🔎 Concept: Inorder traversal + Two-pointer technique.📈 Total Score: 463 ✅.🧠 Optimized BST problems are always fun to solve!.#160DaysOfCode #gfg2025 #cpp #dsa #gfg2025

✅ Day 90/160 - GFG DSA Self-Paced.📌 Problem: Kth Smallest Element in a BST.📂 Topic: Binary Search Tree (BST).💡 Next step: Optimize using in-order traversal with a counter for O(H + k) time. #DSA #BinarySearchTree #cpp #gfgstreak2025 #gfg2025 #160DaysOfCode #kthsmallest

✅ Day 89/160 - GFG DSA Self-Paced.📌 Problem: Check if a Binary Tree is a BST.📂 Topic: Binary Trees | BST Validation.🔍 Approach:.✅ Used a recursive min-max constraint check. #BinarySearchTree #BST #DSA #cpp #gfgstreak2025 #gfg2025 #160DaysOfCode #LearnToCode #CodingJourney