Top Coding Interview Questions ๐ป
๐ 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.
๐ 2. Reverse a Linked List
Reverse a singly linked list iteratively or recursively.
๐ 3. Binary Tree Traversals
Implement Inorder, Preorder, and Postorder traversals (recursion or stack).
๐ 4. Detect Cycle in a Linked List
Use Floydโs Tortoise and Hare algorithm to detect if a loop exists.
๐ 5. Merge Intervals
Given intervals, merge all overlapping intervals.
๐ 6. Valid Parentheses
Use a stack to check for matching pairs of parentheses/brackets.
๐ 7. Maximum Subarray Sum (Kadaneโs Algorithm)
Find the contiguous subarray with the largest sum.
๐ 8. Search in a Rotated Sorted Array
Modified binary search to find an element in a rotated sorted array.
๐ 9. Implement Queue using Stacks
Use two stacks to simulate a queueโs FIFO behavior.
๐ ๐ Least Recently Used (LRU) Cache Implementation
Use a hashmap + doubly linked list for O(1) access and updates.
๐ก Pro Tip: Master these core problems and practice explaining your thought process clearly. Also, get comfortable with coding on whiteboard or online editors.
August 12, 2026 62 2
