Arcesium Software Developer Intern Interview Questions, Process, and Tips

Round duration - 45 minutes
Round difficulty - Medium

2 coding questions were given to solve in 45 minutes.

Q1. 
Determine the Left View of a Binary Tree
You are given a binary tree of integers. Your task is to determine the left view of the binary tree. The left view consists of nodes that are visible when the tree...read more
Ans. 
A level order traversal based solution can be presented here. For each level, we need to print the first node i.e. the leftmost node of that level.
Steps :
1. Make a queue of node type and push the root node in the queue. 
2. While the queue is not empty, do :
2.1 Determine the current size of the queue. 
2.2 Run a for loop to traverse all nodes of the current level and do :
2.2.1 Remove the topmost node from the q...read more
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Q2. 
Number of Islands Problem Statement
You are given a non-empty grid that consists of only 0s and 1s. Your task is to determine the number of islands in this grid.
An island is defined as a group of 1s (re...read more
Ans. 
The question boils down to finding the number of connected components in an undirected graph. Now comparing the connected components of an undirected graph with this problem, the node of the graph will be the “1’s” (land) in the matrix. 
BFS or DFS can be used to solve this problem. In each BFS call, a component or a sub-graph is visited. We will call BFS on the next un-visited component. The number of calls to BFS...read more
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Round duration - 60 minutes
Round difficulty - Medium

This was a 60 min technical interview round. The interviewer asked me to code 2 programming questions. 
Tip : Practice more to clear DSA problems. Medium level questions will be enough to clear the rounds.

Q1. 
Topological Sort Problem Statement
Given a Directed Acyclic Graph (DAG) consisting of V vertices and E edges, your task is to find any topological sorting of this DAG. You need to return an array of size ...read more
Ans. 
Topological sorting of vertices of a Directed Acyclic Graph is an ordering of the vertices v1,v2,v3.....vn in such a way, that if there is an edge directed towards vertex vj from vertex vi , then vi comes before vj. Modified DFS can be used to solve topological sort problem. A stack can be used to implement it. Steps :
1. Make a stack to store the nodes and a Boolean array to mark all visited nodes initialized to false....read more
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Q2. 
N-th Node From The End Problem Statement
You are provided with a Singly Linked List containing integers. Your task is to determine the N-th node from the end of the list.
Example:
Input:
If the list is...read more
Ans. 
A direct approach is to traverse the entire linked list and calculate its length. Traverse the list again and return the (length-N+1) node. But this approach involves two traversals of the linked list. 
To further optimize the solution, the question can be solved in one traversal only. Two pointers can be used here. Steps :
1. Initialize both the slow pointer and the fast pointer to the head node.
2. First, move fast...read more
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Round duration - 45 minutes
Round difficulty - Medium

It was an online coding round where we were supposed to solve 2 coding questions in 45 minutes.

Q1. 
Maximum Meetings Problem Statement
Given the schedule of N meetings with their start time Start[i] and end time End[i], you need to determine which meetings can be organized in a single meeting room such ...read more
Ans. 
Greedy approach can be applied to solve this problem. We sort the start and end time pairs for each meeting on the basis of the end time. Then we compare if the next meeting's start time is greater than the previous meeting's end time. If the start time is greater, we can count this meeting and we increase our meeting counter otherwise this meeting can't take place. In this manner, we traverse through all the meeting p...read more
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Q2. 
Connecting Ropes with Minimum Cost
You are given 'N' ropes, each of varying lengths. The task is to connect all ropes into one single rope. The cost of connecting two ropes is the sum of their lengths. Yo...read more
Ans. 
Concept of min heap can be applied here. In each iteration, we need to pick the rope with minimum length because the value picked first will be included in the final answer multiple times. Hence, for minimum cost, we pick the longer length ropes later. 
Approach :
First of all, build minHeap (priority queue) from the given array of rope length. 
In each iteration:
1) Extract two ropes with minimum length from the...read more
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Round duration - 60 minutes
Round difficulty - Medium

The interview was conducted online. The interviewer asked me 2 programming questions and questions on OOPS concepts.

Q1. 
Bottom View of Binary Tree
Given a binary tree, determine and return its bottom view when viewed from left to right. Assume that each child of a node is positioned at a 45-degree angle from its parent.
N...read more
Ans. 
The basic idea is to use modified pre-order traversal. In this modified pre-order traversal, we keep track of horizontal distance of the node being visited from the root. We also keep track of height of that node. During this traversal, we use an ordered map that stores node's horizontal distance as key and value as tuple (current node's value, current node's level) if the node being visited is the bottommost node seen...read more
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Q2. 
Serialize and Deserialize Binary Tree Problem Statement
Given a binary tree of integers, your task is to implement serialization and deserialization methods. You can choose any algorithm for serialization...read more
Ans. 
DFS can be used for serializing and de-serializing. Process root node and then make recursive calls for left and right child.
For serializing the tree into a list : 
1. If node is null, store -1 in list to denote a null link. Return. 
2. Store the data at current node in list.
3. Call function recursively for left and right subtrees.
4. Return the list.
If we serialize using preorder traversal, apply the same preor...read more
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Q3. Can you explain the concept of virtual destructors in C++?
Ans. 
Using a virtual destructor, we can release the memory allocated by a derived class object or instance. In addition, we can delete instances of the derived class using a base class object pointer. The base class destructor uses the virtual keyword so that both the base class and the derived class destructor will be called at run time. However, the derived class will be called first and then the base class to free up the
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Round duration - 45 minutes
Round difficulty - Hard

Timing (Between 6pm -7pm)
Environment was friendly and 2 coding questions were given.

Q1. 
Connecting Ropes with Minimum Cost
You are given 'N' ropes, each of varying lengths. The task is to connect all ropes into one single rope. The cost of connecting two ropes is the sum of their lengths. Yo...read more
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Q2. 
Optimize Memory Usage Problem Statement
Alex wants to maximize the use of 'K' memory spaces on his computer. He has 'N' different document downloads, each with unique memory usage, and 'M' computer games,...read more
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Round duration - 40 minutes
Round difficulty - Medium

Timing (6pm -7 pm)
Environment was user friendly
In first 10-15 minutes He asked my current company’s work and some behavioral questions. Then he jumped to coding problems

Q1. 
Spiral Order Traversal of a Binary Tree
Given a binary tree with N nodes, your task is to output the Spiral Order traversal of the binary tree.
Input:
The input consists of a single line containing elem...read more
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Round duration - 45 minutes
Round difficulty - Hard

Round was scheduled in the early afternoon hours most probably from 1 to 2 on hackerrank.

Q1. 
BST to Greater Tree Problem Statement
Given a binary search tree (BST) with 'N' nodes, the task is to convert it into a Greater Tree.
A Greater Tree is defined such that every node's value in the origina...read more
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Q2. 
Ninja and Binary String Problem Statement
Ninja has a binary string S of size N given by his friend. The task is to determine if it's possible to sort the binary string S in decreasing order by removing a...read more
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Round duration - 40 minutes
Round difficulty - Medium

This round was conducted on Code Share platform. I was shared the invitation link one day prior to the interview and also was told the name of my interviewer. I looked at the profile of the interviewer at linked.in and got a better understanding of what kind of person he was and prepared accordingly. The round was scheduled at 3 :00 pm on 25th August and I was eagerly waiting for the clock hands to reach 3 o'clock since morning and finally I went in front of him after wearing a white shirt and a black coat over it along with a tie over it.

Q1. 
Spiral Order Traversal of a Binary Tree
Given a binary tree with N nodes, your task is to output the Spiral Order traversal of the binary tree.
Input:
The input consists of a single line containing elem...read more
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