Top Coding Interview Questions 💻

📍 1. Two Sum Problem
Find two numbers in an array that add up to a target value.
Approach: Use a hash map to store complements for O(n) time.

📍 2. Reverse a Linked List
Reverse a singly linked list iteratively or recursively.

📍 3. Binary Tree Traversals
Implement Inorder, Preorder, and Postorder traversals (recursion or stack).

📍 4. Detect Cycle in a Linked List
Use Floyd’s Tortoise and Hare algorithm to detect if a loop exists.

📍 5. Merge Intervals
Given intervals, merge all overlapping intervals.

📍 6. Valid Parentheses
Use a stack to check for matching pairs of parentheses/brackets.

📍 7. Maximum Subarray Sum (Kadane’s Algorithm)
Find the contiguous subarray with the largest sum.

📍 8. Search in a Rotated Sorted Array
Modified binary search to find an element in a rotated sorted array.

📍 9. Implement Queue using Stacks
Use two stacks to simulate a queue’s FIFO behavior.

📍 🔟 Least Recently Used (LRU) Cache Implementation
Use a hashmap + doubly linked list for O(1) access and updates.

💡 Pro Tip: Master these core problems and practice explaining your thought process clearly. Also, get comfortable with coding on whiteboard or online editors.