Info Edge Associate Software Engineer Interview Questions and Answers

Given a 2D matrix with doors and walls, fill distance matrix with minimum distance to the nearest door.

• Iterate through the matrix and find the doors

• Use Breadth-First Search (BFS) to calculate the minimum distance from each cell to the nearest door

• Update the distance matrix with the minimum distances

Find kth smallest element in unordered array with O(1) space

• Use the QuickSelect algorithm to partition the array and find the kth smallest element

• Choose a pivot element and partition the array into two subarrays

• Recursively partition the subarray that contains the kth smallest element

• Repeat until the pivot element is the kth smallest element

• Time complexity: O(n) average case, O(n^2) worst case

To find friends of friends who are not already friends with you, we can first find your friends and then their friends excluding yourself and your friends.

• Get your list of friends

• For each friend, get their list of friends

• Exclude yourself and your friends from the final list of friends of friends

Design optimal data structures for LRU cache

• Use a doubly linked list to keep track of recently used items

• Use a hash table to store key-value pairs for quick access

• When an item is accessed, move it to the front of the linked list

• When the cache is full, remove the least recently used item from the back of the linked list and hash table

Convert a sorted array to balanced binary search tree

• Find the middle element of the array and make it the root of the tree

• Recursively construct the left subtree using the left half of the array

• Recursively construct the right subtree using the right half of the array

• Repeat until all elements are added to the tree

Reverse a singly linked list in groups of k in­place

• Divide the linked list into groups of k nodes

• Reverse each group of k nodes

• Connect the reversed groups to form the final linked list

A recursive routine to calculate a ^ n

• The base case is when n is 0, in which case the result is 1

• For any other value of n, the result is a multiplied by the result of a^(n-1)

• The recursive function should call itself with a^(n-1) as the new input

Design optimal data structure for never-ending stream of numbers for insertion, deletion, searching, kth largest and kth smallest.

• Use a balanced binary search tree like AVL or Red-Black tree for efficient insertion, deletion, and searching.

• Maintain two heaps, one for kth largest and one for kth smallest.

• For finding kth largest, use a min heap of size k and for kth smallest, use a max heap of size k.

• Alternatively, use a...read more