Google Junior Software Engineer Interview Questions and Answers

Round duration - 90 minutes
Round difficulty - Medium

Q1. 
Longest Increasing Subsequence Problem Statement
Given 'N' students standing in a row with specific heights, your task is to find the length of the longest strictly increasing subsequence of their heights...read more
Ans. 
Find the length of the longest strictly increasing subsequence of heights of students in a row.
• Iterate through the heights array and for each element, find the length of the longest increasing subsequence ending at that element.

• Use dynamic programming to keep track of the longest increasing subsequence length for each element.

• Return the maximum length found as the result.
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Q2. 
Overlapping Intervals Problem Statement
You are given the start and end times of 'N' intervals. Write a function to determine if any two intervals overlap.
Note:
If an interval ends at time T and anothe...read more
Ans. 
Given start and end times of intervals, determine if any two intervals overlap.
• Iterate through intervals and check if any two intervals overlap by comparing their start and end times

• Sort intervals based on start times for efficient comparison

• Consider edge cases where intervals end and start at the same time
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Q3. What SQL queries were asked during your interview?
Ans. 
Various SQL queries related to data manipulation and retrieval were asked during the interview.
• Basic SELECT queries to retrieve data from a single table

• JOIN queries to retrieve data from multiple tables based on a common column

• Aggregate functions like COUNT, SUM, AVG, etc. to perform calculations on data

• Subqueries to retrieve data based on the result of another query

• UPDATE queries to modify existing data in a table

• DELE...read more
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Round duration - 60 Minutes
Round difficulty - Medium

Q1. 
Zig-Zag String Problem Statement
Given a string STR of size N and an integer M representing the number of rows in the zig-zag pattern, return the string formed by concatenating all rows when the string ST...read more
Ans. 
Arrange a string in zig-zag pattern with given number of rows and concatenate the rows.
• Iterate through the string and distribute characters to rows based on zig-zag pattern

• Concatenate the characters in each row to get the final result

• Handle edge cases like when number of rows is 1 or equal to the length of the string
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Q2. 
Next Permutation Problem Statement
You are given a permutation of 'N' integers. A sequence of 'N' integers is considered a permutation if it includes all integers from 1 to 'N' exactly once. Your task is ...read more
Ans. 
The task is to rearrange a given permutation of 'N' integers to form the lexicographically next greater permutation.
• Iterate from right to left to find the first element that is smaller than the element to its right.

• Swap this element with the smallest element to its right that is greater than it.

• Reverse the elements to the right of the swapped element to get the lexicographically next greater permutation.
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Round duration - 60 Minutes
Round difficulty - Medium

Q1. 
Remove Consecutive Duplicates Problem Statement
Given a string S, your task is to recursively remove all consecutive duplicate characters from the string.
Input:
String S
Output:
Output string
Constr...read more
Ans. 
Recursively remove consecutive duplicate characters from a string.
• Use recursion to check if the current character is the same as the next character, if so skip the next character

• Base case: if the string is empty or has only one character, return the string

• Example: Input: 'aaabcc', Output: 'abc'
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Q2. 
Print Permutations - String Problem Statement
Given an input string 'S', you are tasked with finding and returning all possible permutations of the input string.
Input:
The first and only line of input ...read more
Ans. 
Return all possible permutations of a given input string.
• Use recursion to generate all possible permutations of the input string.

• Swap characters at different positions to generate permutations.

• Handle duplicate characters in the input string by using a set to store unique permutations.
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Round duration - 60 Minutes
Round difficulty - Medium

Q1. Design an e-commerce website similar to Flipkart or Amazon.
Ans. 
Design an e-commerce website similar to Flipkart or Amazon.
• Implement user-friendly interface for easy navigation

• Include search functionality with filters for products

• Incorporate secure payment gateway for transactions

• Provide personalized recommendations based on user behavior

• Include customer reviews and ratings for products

• Implement order tracking and delivery status updates

• Offer various payment options like credit/deb
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Round duration - 120 Minutes
Round difficulty - Easy

The round was conducted in day around 3PM.

Q1. 
Partition Equal Subset Sum Problem
Given an array ARR consisting of 'N' positive integers, determine if it is possible to partition the array into two subsets such that the sum of the elements in both sub...read more
Ans. 
The problem is to determine if it is possible to partition an array into two subsets with equal sum.
• Use dynamic programming to solve this problem efficiently.

• Create a 2D array to store the results of subproblems.

• Check if the sum of the array is even before attempting to partition it.

• Iterate through the array and update the 2D array based on the sum of subsets.

• Return true if a subset with half the sum is found, false ot
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Round duration - 30 Minutes
Round difficulty - Easy

The interview was preponed and was conducted at 9AM.
The interviewer was friendly and I had saw him earlier at pre-placement talk.

Q1. 
Convert Sentence to Pascal Case
Given a string STR, your task is to remove spaces from STR and convert it to Pascal case format. The function should return the modified STR.
In Pascal case, words are con...read more
Ans. 
Convert a given string to Pascal case format by removing spaces and capitalizing the first letter of each word.
• Iterate through each character in the string

• If the character is a space, skip it

• If the character is not a space and the previous character is a space or it is the first character, capitalize it
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Q2. Write an SQL query to retrieve the Nth highest salary from a database.
Ans. 
SQL query to retrieve the Nth highest salary from a database
• Use the ORDER BY clause to sort salaries in descending order

• Use the LIMIT clause to retrieve the Nth highest salary

• Consider handling cases where there might be ties for the Nth highest salary
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Round duration - 30 Minutes
Round difficulty - Easy

This round was conducted 15mins after 1st round.

Q1. 
Remove the Kth Node from the End of a Linked List
You are given a singly Linked List with 'N' nodes containing integer data and an integer 'K'. Your task is to delete the Kth node from the end of this Lin...read more
Ans. 
Remove the Kth node from the end of a singly linked list.
• Traverse the list to find the length 'N'.

• Calculate the position of the node to be removed from the beginning as 'N - K + 1'.

• Remove the node at the calculated position.

• Handle edge cases like removing the head or tail of the list.

• Update the pointers accordingly after removal.
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Q1. What is difference between abstract class and interface?
Ans. 
Abstract class can have implementation while interface cannot. Classes can implement multiple interfaces but only one abstract class.
• Abstract class can have constructors while interface cannot.

• Abstract class can have non-abstract methods while interface cannot.

• Interfaces are used for full abstraction while abstract classes are used for partial abstraction.

• Example: Abstract class - Animal with method eat() and subclass ...read more
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