Sanchhaya Education Software Developer Intern Interview Questions, Process, and Tips

Round duration - 160 minutes
Round difficulty - Easy

The online assessment consisted of four components, a code debugging section (20 minutes), a coding test (70 minutes), a workstyles assessment (20 minutes) and a reasoning ability section (35 minutes). Code debugging questions were pretty simple and straightforward. The coding test consisted of 2 questions, first was similar to two Sum problem. Second question was similar to find the critical edges in a graph. The workstyles assessment section contained certain behavioural questions.
Reasoning ability section consisted of aptitude questions. This round was basically to check the problem solving skills of the candidate.

Q1. Two Sum
You are given an array of integers 'ARR' of length 'N' and an integer Target. Your task is to return all pairs of elements such that they add up to Target.
Note:
We cannot use th...read more
Ans. Hashing Solution
• We can store the frequency of every element in the array in a hashmap.
• We will loop over every index i, and check the frequency of (Target - ARR[i]) is the hashmap:
  • If (Target - ARR[i]) is equal to ARR[i], we will check if frequency of ARR[i] . If it is greater than 1 then we will decrease the frequency of ARR[i] by 2 and add a pair (ARR[i] , ARR[i]) to our answer.
  • Else, if the frequency of ARR[i] and Targ...read more
Answered by CodingNinjas
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Q2. Bridges In A Graph
Given an undirected graph of V vertices and E edges. Your task is to find all the bridges in the given undirected graph. A bridge in any graph is defined as an edge which, when removed, ...read more
Ans. Brute Force
The brute force approach to find all the bridges in a given graph is to check for every edge if it is a bridge or not, by first not considering current edge is not in given graph and then checking if the vertices that it was connecting are still connected or not, using DFS(DepthFirst Search). Given below is an algorithm that will find all bridges in a graph.
 
Algorithm :
1. Initialise a visited array with fa...read more
Answered by CodingNinjas
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Round duration - 50 minutes
Round difficulty - Easy

I was asked two coding questions. First question was related to binary tree and second question was to implement LRU cache.
I had to code both questions. The interviewer asked me the time and space complexity for both the questions.

Q1. Binary Tree Pruning
You have been given a Binary Tree where the value of each node is either 0 or 1. Your task is to return the same Binary Tree but all of its subtrees that don't contain a 1 have been...read more
Ans. PostOrder Traversal based Approach
If we have to process a subtree from the tree, it is better to process the child subtrees first i.e. PostOrder Traversal. This strategy will help us in two ways-
• We can keep track if a 1 is present in the subtree or not.
• If a 1 is not present in a subtree, we can delete it directly (by assign ‘NULL’ to that subtree).
 
Here, is the complete recursive algorithm
• Create a hasOne function...read more
Answered by CodingNinjas
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Q2. LRU Cache Implementation
Design and implement a data structure for Least Recently Used (LRU) cache to support the foll...read more
Ans. Array Approach
We will use an array of type Pair<key, value> to implement our LRU Cache where the larger the index is, the more recently the key is used. Means, the 0th index denotes the least recently used pair, and the last index denotes the most recently used pair.
 
The key will be considered as accessed if we try to perform any operation on it. So while performing the get operation on a key, we will do a ...read more
Answered by CodingNinjas
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Round duration - 30 minutes
Round difficulty - Easy

I was asked two coding questions and some conceptual questions about priority heap data structure. I was able to code the optimized approach for the first question. But second question was a little tricky for me as I had never heard it before.

Q1. Langford Pairing
You are given a positive integer N. Return a list of integers of size 2N containing all the integers from 1 to N (both inclusive) twice arranged according to Langford pairing. If no such p...read more
Ans. Recursion
It can be observed with some examples that for any number N, the permutation following Langford pairing is possible only if either N mod 4 is 0 or 3. Thus, Langford pairing is possible for 3, 4, 7, 8, etc, and not possible for 1, 2, 5, 6, etc. Now to find the sequence,
 
• If N mod 4 is 1 or 2, return -1.
• Otherwise, we will use recursion to generate the sequence.
• Create an array of size 2*N and initialize all ...read more
Answered by CodingNinjas
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Q2. Ninja theater
You have been appointed as the technical lead in the very famous ninja theater. Due to the recent pandemic, all the people inside the theater must follow social distancing. There are ‘N’ seat...read more
Ans. Brute Force
The idea here is to maintain a sorted list of seat numbers of the persons sitting in the theater. For every query of type 2, we can directly remove the seat number from our list. For every query of type 1, we will iterate over the list and find the lowest seat number, which is empty and has a maximum distance from the closest person in the theater and place the new person accordingly.
 
Algorithm:
 
• De...read more
Answered by CodingNinjas
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