Placement PrepCoding Practice
Coding Practice
Curated DSA problems from LeetCode, HackerRank, and past company papers to crack the technical rounds.
1Arrays & Strings
Q: Two Sum
A:
Use a Hash Map to store elements and their indices as you iterate. O(N) time complexity.
Q: Valid Parentheses
A:
Use a Stack. Push opening brackets, pop and compare for closing brackets.
Q: Maximum Subarray (Kadane's Algorithm)
A:
Maintain a current_sum and max_sum. If current_sum becomes negative, reset it to 0.
2Linked Lists & Trees
Q: Reverse a Linked List
A:
Maintain three pointers: prev, current, and next. Iterate and reverse links.
Q: Detect Cycle in Linked List
A:
Use Floyd's Tortoise and Hare algorithm (slow and fast pointers).
Q: Lowest Common Ancestor of a BST
A:
If both nodes are less than root, go left. If both are greater, go right. Else, root is LCA.