QSC, LLC Full Stack Web Developer Interview Questions and Answers

Round duration - 60 minutes
Round difficulty - Medium

It was a 65 minute , 2 coding questions round .
The environment was good , 
The exam was at 12 noon

Q1. LCA Of Binary Tree
You have been given a Binary Tree of distinct integers and two nodes ‘X’ and ‘Y’. You are supposed to return the LCA (Lowest Common Ancestor) of ‘X’ and ‘Y’.
The LCA of ‘X’ and ‘Y’ in ...read more
Ans. Naive Approach
The basic idea of this approach is to list down all the ancestors of the given nodes. And then, we will choose the common ancestor from the two lists which is farthest from the root of the tree.
 
Consider the binary tree as shown in the above figure, where we are trying to find the LCA of X and Y. Let us try to find the path from the root node to X and Y respectively and store the nodes present in the...read more
Answered by CodingNinjas
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Q2. Topological Sort
A Directed Acyclic Graph (DAG) is a directed graph that contains no cycles.
Topological Sorting of DAG is a linear ordering of vertices such that for every directed edge from vertex ‘u’...read more
Ans. Modify Depth First Search
In the Depth First Search (DFS), we start from a vertex, we first print it and then recursively call DFS for its adjacent vertices. In topological sorting, we use a  stack. We don’t print the vertex immediately, we first recursively call topological sorting for all its adjacent vertices, then push it to a stack. Finally, print contents of the stack. Note that a vertex is pushed to stack on...read more
Answered by CodingNinjas
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Round duration - 50 minutes
Round difficulty - Medium

The round was based more upon the OS , DBMS , Networking and Computer Architecture and web based.
Is the tag and tag same? Define Image Map?

Q1. OS Question
I was told to write code for a singleton class
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Round duration - 50 Minutes
Round difficulty - Medium

The round included topics of DSA , OS , OOPS , CN and dbms and a lot about my internship experience.
What are the different data types present in javascript? What are some common clauses used with SELECT query in SQL? What is Cursor? How to use a Cursor?

Q1. Build Heap
You are given an integer array with N elements. Your task is to build a max binary heap from the array.
A max-heap is a complete binary tree in which the value of each internal node is greater...read more
Ans. Top - Down approach
The idea is to follow a top-down approach. The given array, represents a binary tree but does not follow the property of heap, in order to convert the input array to heap array heapify the complete binary tree formed from array in reverse level order following a top-down approach. It can be observed that leaf nodes need not be heapified as they already follow the heap property. Also, the array repres...read more
Answered by CodingNinjas
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