Goldman Sachs Software Developer Intern Interview Questions and Answers

Round duration - 90 minutes
Round difficulty - Hard

Timing was 10 AM. Environment was very well. Questions were well explained.

Q1. 
Minimum Umbrellas Problem
You are provided with ‘N’ types of umbrellas, where each umbrella type can shelter a certain number of people. Given an array UMBRELLA that indicates the number of people each um...read more
Ans. 
Given 'N' types of umbrellas with different capacities, find the minimum number of umbrellas required to shelter exactly 'M' people.
• Iterate through the umbrella capacities and try to cover 'M' people using the minimum number of umbrellas.

• Sort the umbrella capacities in descending order to optimize the solution.

• If it is not possible to cover 'M' people exactly, return -1.
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Q2. 
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. 
The task is to distribute candies to students based on their performance while minimizing the total candies distributed.
• Create an array to store the minimum candies required for each student.

• Iterate through the students' ratings array to determine the minimum candies needed based on the adjacent ratings.

• Consider both left-to-right and right-to-left passes to ensure fair distribution.

• Keep track of the total candies dist...read more
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Round duration - 90 minutes
Round difficulty - Hard

Timing was 10 AM. Environment was very well. Questions were well explained.

Q1. 
Minimum Umbrellas Problem
You are provided with ‘N’ types of umbrellas, where each umbrella type can shelter a certain number of people. Given an array UMBRELLA that indicates the number of people each um...read more
Ans. 
The problem involves finding the minimum number of umbrellas required to shelter a specific number of people based on the capacity of each umbrella.
• Iterate through the array of umbrella capacities and try to cover the required number of people.

• Keep track of the minimum number of umbrellas used to cover the people.

• If it is not possible to cover the exact number of people, return -1.

• Return the minimum number of umbrellas...read more
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Q2. 
Minimum Number of Swaps to Sort an Array
Find the minimum number of swaps required to sort a given array of distinct elements in ascending order.
Input:
T (number of test cases)
For each test case:
N (siz...read more
Ans. 
The minimum number of swaps required to sort a given array of distinct elements in ascending order.
• Use a graph-based approach to find cycles in the array

• Count the number of swaps needed to fix each cycle

• Sum up the swaps needed for all cycles to get the total minimum swaps
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Round duration - 120 minutes
Round difficulty - Easy

This round was held in the evening at 6 o'clock on Hackerrank. It had coding questions: easy, medium, and hard level and MCQ's ( 1 minute for each MCQ). Negative marking was also there

Q1. 
Excel Column Number Problem Statement
Given a column title as it appears in an Excel sheet, return its corresponding column number.
Example:
Input:
"AB"
Output:
28
Explanation:
Column title "AB" co...read more
Ans. 
Convert Excel column title to corresponding column number
• Iterate through the characters in the column title from right to left

• Calculate the corresponding value of each character using its position in the alphabet

• Multiply the value by 26 raised to the power of its position from right

• Sum up all the values to get the final column number
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Q2. 
Climbing the Leaderboard Problem Statement
In a game leaderboard, scores determine rankings where the highest score gets rank 1. Players with identical scores share the same rank, followed by the next ran...read more
Ans. 
Implement a function to determine a player's leaderboard rank for each game score.
• Iterate through the game scores and compare them with the leaderboard scores to determine the rank.

• Handle cases where players have identical scores by assigning them the same rank.

• Ensure the leaderboard scores are in descending order and game scores are in ascending order.

• Return the ranks for each game score in an array.
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Round duration - 30 minutes
Round difficulty - Easy

This was an interview round ( technical round) that was held on video-call and a coding platform was also shared. The interviewer was very friendly with me . She was praising me on every solution that I provided.

Q1. 
Flatten The Multi-Level Linked List
You are given a multi-level linked list of N nodes, where each node can have two pointers: next and child. Flatten this multi-level linked list into a singly linked lis...read more
Ans. 
Flatten a multi-level linked list into a singly linked list and return the head of the flattened list.
• Traverse the linked list in level order

• Use a stack to keep track of nodes with child pointers

• Merge the child nodes into the main list
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Q2. 
The Celebrity Problem
Imagine there are 'N' people at a party, each assigned a unique ID from 0 to N-1. A celebrity at the party is a person who is known by everyone but knows no one else.
Problem Statem...read more
Ans. 
Identify the celebrity at a party where one person knows everyone but is not known by anyone.
• Use a two-pointer approach to eliminate non-celebrities.

• Start with two pointers at the beginning and end, move them based on 'knows' results.

• If A knows B, A cannot be the celebrity; move A pointer. If A does not know B, B cannot be the celebrity; move B pointer.

• Repeat until only one person remains, check if this person is known...read more
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Round duration - 35 minutes
Round difficulty - Easy

This was an interview round ( technical round) that was held on video-call and a coding platform was also shared. The interviewer was very friendly with me . She was praising me on every solution that I provided.

Q1. 
Design a HashSet
Create a HashSet data structure without using any built-in hash table libraries.
Functions Description:
1) Constructor: Initializes the data members as required.

2) add(value): Inserts...read more
Ans. 
Design a HashSet data structure with add, contains, and remove functions.
• Implement a HashSet using an array of linked lists to handle collisions.

• Use a hash function to determine the index in the array for each element.

• For add function, check if the element already exists before inserting.

• For contains function, search for the element in the corresponding linked list.

• For remove function, find and remove the element from ...read more
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Round duration - 20 minutes
Round difficulty - Easy

Online HR+Technical Round .

Round duration - 90 minutes
Round difficulty - Medium

It was on done in hackerrank

Q1. 
Matrix Rank Calculation
Given a matrix ARR of dimensions N * M, your task is to determine the rank of the matrix ARR.
Explanation:
The rank of a matrix is defined as:
(a) The maximum number of linearly...read more
Ans. 
Calculate the rank of a matrix based on the number of linearly independent column or row vectors.
• Determine the rank of the matrix by finding the maximum number of linearly independent column vectors or row vectors.

• Check for linear independence by verifying if there is a nontrivial linear combination that equates to the zero vector.

• Implement a function that takes the matrix dimensions and elements as input and returns t...read more
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Q2. 
Number of Triangles in an Undirected Graph
Determine how many triangles exist in an undirected graph. A triangle is defined as a cyclic path of length three that begins and ends at the same vertex.
Input...read more
Ans. 
Count the number of triangles in an undirected graph using adjacency matrix.
• Iterate through all possible triplets of vertices to check for triangles.

• For each triplet, check if there are edges between all three vertices.

• Increment the count if a triangle is found.

• Return the total count of triangles for each test case.
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Round duration - 20 minutes
Round difficulty - Medium

Interviewer was quite friendly

Round duration - 120 minutes
Round difficulty - Medium

A 120-minute online test was conducted on HackerRank which had the following format:
1st Section :
2 Coding questions(30 minutes)
2nd Section :
10 MCQ questions(30 minutes)
3rd Section :
1 Advanced Programming Question(45 minutes)
4th Section :
2 Subjective Questions(15 minutes)
The coding questions and MCQ questions were a bit tricky so you need to manage your time properly and try to solve all the questions correctly..
Technical – included c and c++ output question, os(scheduling, semaphore), dbms(normal form, etc).

 

Q1. 
Consecutive Sum Representation of a Number
Find the number of ways the given number 'N' can be expressed as the sum of two or more consecutive natural numbers.
Example:
Input:
N = 9
Output:
2
Explan...read more
Ans. 
Find the number of ways a given number can be expressed as the sum of two or more consecutive natural numbers.
• Use a sliding window approach to iterate through all possible consecutive sums.

• Keep track of the sum of the current window and adjust the window size accordingly.

• Count the number of valid consecutive sum representations of the given number.

• Example: For N = 9, valid representations are 2 + 3 + 4 and 4 + 5, so th...read more
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Q2. 
Count Pairs with Given Sum
Given an integer array/list arr and an integer 'Sum', determine the total number of unique pairs in the array whose elements sum up to the given 'Sum'.
Input:
The first line c...read more
Ans. 
Count the total number of unique pairs in an array whose elements sum up to a given value.
• Use a hashmap to store the frequency of each element in the array.

• Iterate through the array and for each element, check if (Sum - element) exists in the hashmap.

• Increment the count of pairs if the complement exists in the hashmap.
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Round duration - 45 minutes
Round difficulty - Medium

interview started with a typical tell me about yourself question. The interviewer was nice and friendly. 

He asked me to explain a little about my projects (only basics).
Which all data structures you know and my favourite data structure. I replied with a linked list.
He asked the difference between array and linked list, time complexities of insertion, deletion, etc. in both of them. Then he asked about sorting an array, different algorithms, and their time complexities.
How would you sort a linked list? How would you find the middle of the linked list in one pass? How would you merge two linked lists (I had to write code for the same)?
Then he asked how would you be able to manage the business and finance decisions at GS.
Tell me an incident when you had the chance to display your leadership skills.
Lastly, I was allowed to ask questions from the interviewer.

Q1. 
Cousin Nodes in a Binary Tree
Determine if two nodes in a binary tree are cousins. Nodes are considered cousins if they are at the same level and have different parents.
Explanation:
In a binary tree, e...read more
Ans. 
Determine if two nodes in a binary tree are cousins based on level and parent criteria.
• Traverse the tree to find the levels and parents of the given nodes.

• Check if the nodes are at the same level and have different parents.

• Return 'YES' if the nodes are cousins, 'NO' otherwise.
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Round duration - 45 minutes
Round difficulty - Medium

This round was relatively short and mostly consisted of coding (on hackerrank’s codepair platform)

The interviewer asked me about my previous interview and what all questions were asked in it.
Then there was a discussion about my projects and the technologies used in them. How would you deploy an application and what happens in the process of entering a keyword in the browser and loading your requested page? 
He asked me to write the code for finding the middle of a linked list in one pass.
After that, I had to write the code for the implementation of a queue. I first discussed the approaches with him using array and linked lists for some time. They wrote the code using a linked list by taking head and tail pointer.
He was satisfied with it and the round ended with me asking him the questions I had.

Q1. 
Middle of a Linked List
You are given the head node of a singly linked list. Your task is to return a pointer pointing to the middle of the linked list.
If there is an odd number of elements, return the ...read more
Ans. 
Return the middle element of a singly linked list, or the one farther from the head if there are even elements.
• Traverse the linked list with two pointers, one moving twice as fast as the other

• When the fast pointer reaches the end, the slow pointer will be at the middle

• If there are even elements, return the one that is farther from the head node

• Handle edge cases like linked list of size 1 or empty list
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Round duration - 135 Minutes
Round difficulty - Medium

The platform was HackerRank with tab proctoring and webcam proctoring enabled. 
Timings were during day time around 10 am

Q1. 
Largest Rectangle in Histogram Problem Statement
You are given an array/list HEIGHTS of length N, where each element represents the height of a histogram bar. The width of each bar is considered to be 1.
...read more
Ans. 
Compute the area of the largest rectangle that can be formed within the bounds of a given histogram.
• Iterate through the histogram bars and maintain a stack to keep track of increasing heights.

• Calculate the area of the rectangle by considering the current height as the height of the rectangle and the width as the difference between the current index and the index at the top of the stack.

• Update the maximum area found so ...read more
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Q2. 
Find the Longest Palindromic Substring
Given a string ‘S’ composed of lowercase English letters, your task is to identify the longest palindromic substring within ‘S’.
If there are multiple longest palin...read more
Ans. 
Find the longest palindromic substring in a given string, returning the rightmost one if multiple substrings are of the same length.
• Use dynamic programming to check for palindromes within the string.

• Start by checking for palindromes of length 1 and 2, then expand to longer substrings.

• Keep track of the longest palindromic substring found so far and return the rightmost one if multiple substrings are of the same length.
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Round duration - 30 Minutes
Round difficulty - Medium

During day time
Platform: Zoom
The round starts with some introduction of mine, followed by my interests in life and what should I see in the company where I want to work

Q1. 
Smallest Window Problem Statement
Given two strings S and X containing random characters, the task is to find the smallest substring in S which contains all the characters present in X.
Input:
The first...read more
Ans. 
Find the smallest substring in a given string that contains all characters from another string.
• Use a sliding window approach to find the smallest window in S that contains all characters in X.

• Keep track of the characters in X using a hashmap.

• Move the right pointer to expand the window until all characters in X are found, then move the left pointer to shrink the window while maintaining the condition.

• Return the smallest...read more
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