CLSA Software Engineer Interview Questions and Answers

Round duration - 90 minutes
Round difficulty - Medium

There were 33 questions in total. The objective questions were simple.

Q1. 
Sort Big List Dates Problem Statement
Mary is an enthusiastic party-goer who struggles with remembering event dates. Help Mary by sorting a given list of event dates in an ascending order.
Example:
Inpu...read more
Ans. 
Sort a list of event dates in ascending order based on year, month, and day.
• Sort the list of dates based on year, then month, and finally day.

• Use a sorting algorithm to rearrange the dates in ascending order.

• Ensure the constraints are met for each date in the list.
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Q2. 
Pair Sum Problem Statement
You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to find and return a list of all pairs of elements where each sum of a pair equals 'S'.
Note:
...read more
Ans. 
Given an array and a target sum, find all pairs of elements that add up to the target sum.
• Iterate through the array and for each element, check if the complement (target sum - current element) exists in a hash set.

• If the complement exists, add the pair to the result list.

• Sort the pairs based on the first element and then the second element.

• Handle edge cases like duplicate elements and pairs with the same values.

• Example...read more
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Q3. 
Maximum Sum Problem Statement
Given an integer N, your task is to recursively break it into three integer parts: N / 2, N / 3, and N / 4. You need to compute the maximum sum possible by dividing the numbe...read more
Ans. 
Given an integer N, recursively break it into three parts and find the maximum sum possible.
• Recursively divide N into N/2, N/3, and N/4 to find the maximum sum

• Compare the sum obtained by dividing N with the sum of N itself

• Return the maximum sum for each test case
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Round duration - 60 minutes
Round difficulty - Medium

Technical Interview round with questions based on DSA.

Q1. 
Duplicate Integer in Array
Given an array ARR of size N, containing each number between 1 and N-1 at least once, identify the single integer that appears twice.
Input:
The first line contains an integer...read more
Ans. 
Identify the duplicate integer in an array containing numbers between 1 and N-1.
• Iterate through the array and keep track of the frequency of each element using a hashmap.

• Return the element with a frequency greater than 1 as the duplicate integer.

• Ensure the constraints are met and a duplicate number is guaranteed to be present.
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Q2. 
Sum Root to Leaf Numbers
You are given an arbitrary binary tree consisting of N nodes, each associated with an integer value from 1 to 9. Each root-to-leaf path can be considered a number formed by concat...read more
Ans. 
Calculate the total sum of all root to leaf paths in a binary tree formed by concatenating node values.
• Traverse the binary tree from root to leaf nodes, keeping track of the current path sum

• Add the current node value to the path sum and multiply by 10 for each level

• When reaching a leaf node, add the final path sum to the total sum

• Return the total sum modulo (10^9 + 7)
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Q3. 
Topological Sort Problem Statement
You are given a directed acyclic graph (DAG). Your task is to perform topological sorting of the graph and return any valid ordering.
Explanation:
A directed acyclic g...read more
Ans. 
Implement a function to perform topological sorting on a directed acyclic graph (DAG) and return any valid ordering.
• Create a graph data structure to represent the DAG

• Use depth-first search (DFS) to perform topological sorting

• Maintain a visited array to keep track of visited nodes

• Return the ordering of nodes after DFS traversal
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Round duration - 60 minutes
Round difficulty - Easy

Technical interview round with questions based on DSA.

Q1. 
LCA of Binary Tree Problem Statement
You are given a binary tree consisting of distinct integers and two nodes, X and Y. Your task is to find and return the Lowest Common Ancestor (LCA) of these two nodes...read more
Ans. 
Find the Lowest Common Ancestor (LCA) of two nodes in a binary tree.
• Traverse the binary tree to find the paths from the root to nodes X and Y.

• Compare the paths to find the last common node, which is the LCA.

• Handle cases where one node is an ancestor of the other.

• Consider edge cases like when X or Y is the root node.

• Implement a recursive or iterative solution to find the LCA efficiently.
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Q2. 
Rotated Array Minimum Finder
You are provided with a sorted array that has undergone 'K' rotations (the exact value of 'K' is unknown). A rotation involves shifting each element of the array to the right,...read more
Ans. 
Implement a function to find the minimum number in a rotated sorted array efficiently.
• Use binary search to find the minimum element in the rotated array.

• Compare the mid element with the start and end elements to determine which half of the array to search next.

• Continue the binary search until the minimum element is found.
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Q3. 
Maximum Binary Tree Construction Problem
Given an array TREE of 'N' unique integers, construct a maximum binary tree using the following rules:
1. The root of this tree is the maximum number in TREE.
2. T...read more
Ans. 
Construct a maximum binary tree from an array of unique integers following specific rules.
• Find the maximum number in the array to set as the root of the tree.

• Recursively construct the left subtree with elements before the maximum number.

• Recursively construct the right subtree with elements after the maximum number.
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Easy basic questions on ds algo, swap two numbers with out extra space

Q1. LLD library management system with apis table schema java classes and their interaction
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Round duration - 90 minutes
Round difficulty - Medium

It was a cumulative test

Q1. 
Trapping Rainwater Problem Statement
You are given an array ARR of long type, which represents an elevation map where ARR[i] denotes the elevation of the ith bar. Calculate the total amount of rainwater t...read more
Ans. 
Calculate the total amount of rainwater that can be trapped within given elevation map.
• Iterate through the array to find the maximum height on the left and right of each bar.

• Calculate the amount of water that can be trapped above each bar by taking the minimum of the maximum heights on the left and right.

• Sum up the trapped water above each bar to get the total trapped water for the elevation map.
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Round duration - 90 minutes
Round difficulty - Medium

It was sophisticated in nature and a good brain buster.

Q1. 
Candies Distribution Problem Statement
Prateek is a kindergarten teacher with a mission to distribute candies to students based on their performance. Each student must get at least one candy, and if two s...read more
Ans. 
Determine the minimum number of candies needed to distribute to students based on their performance and ratings.
• Iterate through the array of student ratings and assign 1 candy to each student initially.

• Then iterate from left to right and check if the current student's rating is higher than the previous student, if so, assign candies accordingly.

• Similarly, iterate from right to left to handle cases where the current stu...read more
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Round duration - 1 hour
Round difficulty - Medium

Q1. DBMS
It revolved around basic concepts
Ans. 
DBMS is a software system that manages databases and allows users to interact with data stored in them.
• DBMS stands for Database Management System

• It helps in creating, updating, and managing databases

• Examples of DBMS include MySQL, Oracle, SQL Server

• It ensures data integrity, security, and efficient retrieval
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Round duration - 70 minutes
Round difficulty - Hard

It was a great experience