Longest Palindromic Subsequence Design a stack that supports getMin() in O(1) time and O(1) extra space Depth First Traversal or DFS for a Graph Count Inversions in an array Extract Leaves of a Binary Tree in a Doubly Linked List Check if a given sequence of moves for a robot [...]
Find ways an Integer can be expressed as sum of n-th power of unique natural numbers Word Break Problem using Backtracking
What is the interviewer trying to achieve by asking you to “Tell him about yourself”? His ultimate goal for this interview is to find out enough about you to decide if you’re a good fit for the job opening. He is hoping that this question will get you talking. His [...]
Extract maximum numeric value from a given string Sorted subsequence of size 3 Find four elements a, b, c and d in an array such that a+b = c+d Find Excel column name from a given column number Maximum product of a triplet (subsequnece of size 3) in array Find [...]
Given a binary string, count number of substrings that start and end with 1 Given a string, find its first non-repeating character Generate n-bit Gray Codes Function to check if a singly linked list is palindrome Floor in a Sorted Array Find the transition point in a binary array Find [...]
Maximize value of (arr[i] – i) – (arr[j] – j) in an array Maximum sum of i*arr[i] among all rotations of a given array Maximum Sum Path in Two Arrays Merge two sorted lists (in-place) Minimum sum of squares of character counts in a given string after removing k characters [...]
Print level order traversal line by line Print all nodes in a binary tree having K leaves Print K’th element in spiral form of matrix Print Common Nodes in Two Binary Search Trees Vertical Sum in a given Binary Tree Number of buildings facing the sun Number of Groups of [...]
Sorted Linked List to Balanced BST Sort linked list which is already sorted on absolute values Sort a linked list of 0s, 1s and 2s Sort an array of 0s, 1s and 2s Explanation :-Dutch national flag sorting problem Reverse a stack using recursion Sort a stack using recursion Search [...]
XOR of all subarray XORs Explanation :- Bitwise XOR of all sub-arrays of an integer array in O(n) Iterative function to check if two trees are identical Count all distinct pairs with difference equal to k Given two unsorted arrays, find all pairs whose sum is x Union and Intersection [...]
Big-O analysis Prepare space and time complexity of the problems. Input validation Validate all your input, which is true for both production code and interviews. However, many people assume inputs are all validated without even asking. Ask interviewers for clarification, which can save you from unnecessary checkings. For instance, you [...]