PwC React Js Frontend Developer Interview Questions and Answers

Round duration - 135 minutes
Round difficulty - Easy

Coding questions was easy if you know the basic of coding in any language. I submitted optimized solution for every questions that's why i got selected in this round.

Q1. 
Find K'th Character of Decrypted String
You are given an encrypted string where repeated substrings are represented by the substring followed by its count. Your task is to find the K'th character of the d...read more
Ans. 
Given an encrypted string with repeated substrings represented by counts, find the K'th character of the decrypted string.
• Parse the encrypted string to extract substrings and their counts

• Iterate through the substrings and counts to build the decrypted string

• Track the position in the decrypted string to find the K'th character
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Q2. 
Cycle Detection in Undirected Graph Problem Statement
You are provided with an undirected graph containing 'N' vertices and 'M' edges. The vertices are numbered from 1 to 'N'. Your objective is to determi...read more
Ans. 
Detect if an undirected graph contains a cycle.
• Use Depth First Search (DFS) to traverse the graph and detect cycles.

• Maintain a visited array to keep track of visited vertices.

• If a visited vertex is encountered again during DFS, a cycle exists.

• Check for back edges while traversing the graph.

• Consider disconnected graphs as well.
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Round duration - 150 minutes
Round difficulty - Medium

Q1. 
Pair Sum Problem Statement
You are provided with an array ARR consisting of N distinct integers in ascending order and an integer TARGET. Your objective is to count all the distinct pairs in ARR whose sum...read more
Ans. 
Count distinct pairs in an array whose sum equals a given target.
• Use two pointers approach to iterate through the array and find pairs with sum equal to target.

• Keep track of visited pairs to avoid counting duplicates.

• Return -1 if no such pair exists with the given target.
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Q2. 
Next Smaller Palindrome Problem Statement
You are given a palindrome number represented as a string S. Your task is to find the largest palindrome number that is strictly less than S.
Example:
Input:
T...read more
Ans. 
Given a palindrome number represented as a string, find the largest palindrome number that is strictly less than the given number.
• Iterate from the middle towards the start and end of the string to find the next smaller palindrome.

• If the number is odd in length, simply mirror the left half to the right half to get the next smaller palindrome.

• If the number is even in length, decrement the middle digit and mirror the left...read more
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Q3. 
Longest Common Subsequence Problem Statement
Given two strings STR1 and STR2, determine the length of their longest common subsequence.
A subsequence is a sequence that can be derived from another sequen...read more
Ans. 
The problem involves finding the length of the longest common subsequence between two given strings.
• Use dynamic programming to solve this problem efficiently.

• Create a 2D array to store the lengths of common subsequences of substrings.

• Iterate through the strings to fill the array and find the length of the longest common subsequence.

• Example: For input STR1 = 'abcde' and STR2 = 'ace', the longest common subsequence is 'a
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Round duration - 30 minutes
Round difficulty - Easy

Interview went well.The interviewer asked me how the previous interviews were.

Q1. 
Boundary Traversal of a Binary Tree
Given a binary tree of integers, your task is to output the boundary nodes of this binary tree in Anti-Clockwise order, starting from the root node.
Explanation:
The b...read more
Ans. 
Output the boundary nodes of a binary tree in Anti-Clockwise order, starting from the root node.
• Traverse the left boundary nodes in top-down order

• Traverse the leaf nodes from left to right

• Traverse the right boundary nodes in bottom-up order

• Combine the above traversals to get the boundary nodes in Anti-Clockwise order
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Q2. 
Sort 0 1 2 Problem Statement
Given an integer array arr of size 'N' containing only 0s, 1s, and 2s, write an algorithm to sort the array.
Input:
The first line contains an integer 'T' representing the n...read more
Ans. 
Sort an array of 0s, 1s, and 2s in linear time complexity.
• Use three pointers to keep track of the positions of 0s, 1s, and 2s in the array.

• Iterate through the array and swap elements based on the values encountered.

• Maintain left pointer for 0s, right pointer for 2s, and current pointer for traversal.

• Example: If current element is 0, swap it with element at left pointer and increment both pointers.
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Round duration - 20 minutes
Round difficulty - Easy

This round is very easy, In this round they basically need confidence and truthful person.

Q1. Write a java program to sort an array
Ans. 
Java program to sort an array of strings
• Use Arrays.sort() method to sort the array of strings

• Import java.util.Arrays package

• Example: String[] arr = {"apple", "banana", "orange"}; Arrays.sort(arr);
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Q2. Collections in java and springboot
Ans. 
Collections in Java and Spring Boot are used to store and manipulate groups of objects.
• Collections in Java are used to store multiple objects in a single unit.

• Spring Boot provides support for managing collections through various data structures like List, Set, Map, etc.

• Collections in Java and Spring Boot help in organizing and manipulating data efficiently.

• Example: List names = new ArrayList<>();
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