🔥Day 108 #gfg160.Solved "K Sized Subarray Maximum".Used deque to maintain potential max indices and slide the window efficiently across the array. Optimized for time with no redundant comparisons. 📌TC: O(n) | SC: O(k).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks

🔥Day 107 #gfg160.Solved "Decode the String".Simulated decoding of nested patterns like "3[a2[c]]" using StringBuilder as a stack substitute. Handled brackets, digits, and sequences efficiently. 📌TC: O(n²) | SC: O(n).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks

🔥Day 106 #gfg160.Solved "Postfix Evaluation".Used a stack to process operands and operators in postfix order. Handled + - * / efficiently for valid expressions. 📌TC: O(n) | SC: O(n).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks @geeksforgeeks

🔥Day 105 #gfg160.Solved "Get Min from Stack".Used encoded values to track min in O(1) space & time. Clever use of math to update min while maintaining actual stack order!.📌TC: O(1) | SC: O(1).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks @geeksforgeeks

🔥Day 104 #gfg160.Solved "Max of Min for Every Window Size".Used stacks to find window spans and track max of minimums for each size. Cool stack trick with O(n) time!.📌TC: O(n) | SC: O(n).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks @geeksforgeeks

🔥Day 103 #gfg160.Solved "Histogram Max Rectangular Area".Used a monotonic stack to calculate the largest possible rectangle. Stack tracks indices of increasing bars and compute area when a smaller height is found. 📌TC:O(n) | SC:O(n).#geekstreak2025 #100DaysOfCode #geeksforgeeks

🔥Day 102 #gfg160.Solved "Stock Span Problem".Used a monotonic stack to compute span values for each day efficiently. Popped smaller elements and calculated distance from previous greater element. 📌TC: O(n) | SC: O(n).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks

🔥Day 101 #gfg160.Solved "Next Greater Element".Used a monotonic stack to track the next greater element for each value in reverse order. Efficient, clean, and optimised for space & time!.📌TC: O(n) | SC: O(n).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks.@geeksforgeeks

🔥Day 100 #gfg160.Solved "Longest Valid Parentheses".Used two-pass scanning (L→R & R→L) to track unmatched '(' and ')' while maximising valid lengths. Smart use of counters, no extra space!.📌TC:O(n) | SC:O(1).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks.@geeksforgeeks

🔥Day 99 #gfg160.Solved "Parenthesis Checker".Used a stack to ensure all opening brackets are properly closed in correct order and type. Brackets like {}, [], () are validated efficiently. 📌TC: O(n) | SC: O(n).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks.@geeksforgeeks

🔥Day 98 #gfg160.Solved "Find Median in a Stream".Used two heaps — maxHeap (left) & minHeap (right) — to balance elements. Efficiently inserted numbers and maintained medians in real time. 📌TC: O(log n) | SC: O(n).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks

🔥Day 97 #gfg160.Solved "Merge K Sorted Linked Lists".Used divide & conquer to recursively merge pairs of lists. Reduced K-way merge to efficient 2-way merges for optimised performance. 📌TC: O(N log K) | SC: O(1) aux.#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks

🔥Day 96 #gfg160.Solved “K Closest Points to Origin” using a Max Heap.Stored K closest points by comparing squared Euclidean distances. Max Heap ensures farthest is dropped when needed. 📌TC: O(N log K) | SC: O(K).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks

🔥Day 95 #gfg160.Solved “K Largest Elements” .Used a Min Heap of size K to efficiently keep track of top K largest elements. Extracted all, reversed them for descending order. 📌 TC: O(N log K) | SC: O(K).#geekstreak2025 #100DaysOfCode #geeksforgeeks @geeksforgeeks

🔥Day 94 #gfg160.Solved "Serialize and Deserialize a Binary Tree".Used Level Order Traversal (BFS) to serialize the tree and reconstruct it with a queue-based approach for deserialization. 📌TC: O(N) | SC: O(N).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks.@geeksforgeeks

🔥Day 93 #gfg160.Solved "Lowest Common Ancestor in a BST".Used BST properties to efficiently trace paths from root to nodes. Traversed left or right based on node values. 📌 Time: O(H) | Space: O(1).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks.@geeksforgeeks

🔥Day 92 #gfg160.Solved "Fixing Two Nodes of a BST".Used inorder traversal to identify the misplaced nodes. Once detected, swapped the incorrect nodes to restore BST structure. 📌 Time: O(N) | Space: O(H).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks.@geeksforgeeks

🔥Day 91 #gfg160.Solved "Pair Sum in BST".Used DFS + HashSet to track visited nodes. If (target - current) already exists, pair is found. 📌TC: O(N) | SC: O(N).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks @geeksforgeeks

🔥Day 90 #gfg160.Solved "K-th Smallest in BST".Used Inorder Traversal since it gives sorted elements in BST. Counted nodes while traversing and returned the Kth one. 📌TC: O(K) | SC: O(H).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks @geeksforgeeks

🔥Day 89 #gfg160.Solved "Check for BST".Used Morris Inorder Traversal to verify strictly increasing order without extra space. No recursion or stack used, only constant space. 📌TC: O(N) | SC: O(1).#gfg160 #geekstreak2025 #100DaysOfCode #geeksforgeeks @geeksforgeeks