20+ Goldman Sachs Software Analyst Interview Questions and Answers

Count the number of occurrences of a given word in a 2D grid by moving in all eight possible directions.

• Iterate through each cell in the grid and start searching for the word from that cell in all eight directions.

• Keep track of the number of occurrences found while searching.

• Handle edge cases like word length exceeding grid dimensions or starting from out-of-bounds cells.

The problem involves executing range sum and point update queries on an array using Fenwick Tree data structure.

• Use Fenwick Tree to efficiently handle range sum and point update queries.

• For range sum queries, calculate prefix sums and use them to compute the sum in the given range.

• For point update queries, update the Fenwick Tree accordingly to reflect the changes in the array.

• Ensure to handle the queries efficiently to meet the time constraints.

• Example: Given array [3, 2, 1,...read more

The task is to determine a player's leaderboard rank for each game score based on given leaderboard and game scores.

• Iterate through each game score and compare it with leaderboard scores to determine the rank.

• Use a hashmap to store the leaderboard scores and their corresponding ranks.

• Handle cases where multiple players have the same score and share the same rank.

• Return an array of ranks for each game score.

The task is to flatten a multi-level linked list into a singly linked list and return the head of the modified linked list.

• Traverse the linked list and keep track of nodes with child pointers

• Flatten the child linked list and merge it with the main linked list

• Update the 'next' pointers to create a singly linked list

• Return the head of the modified linked list

Design a HashSet data structure with add, contains, and remove functions.

• Implement a HashSet using an array and handling collisions using chaining or open addressing.

• Use a hash function to map values to indices in the array.

• For add function, insert the value at the hashed index.

• For contains function, check if the value exists at the hashed index.

• For remove function, delete the value at the hashed index and return it, or return -1 if not found.

Split array into two subsets with minimum absolute difference between their sums.

• Use dynamic programming to find the minimum absolute difference between the sums of two subsets.

• Iterate through all possible sums of subsets and find the minimum difference.

• Consider each element either being included in the first subset or the second subset.

• Keep track of the minimum absolute difference found so far.

• Return the minimum absolute difference between the sums of the two subsets.

Given a binary tree, a target node, and an integer K, find all nodes at distance K from the target node.

• Traverse the binary tree to find the target node.

• Use BFS to traverse the tree from the target node to nodes at distance K.

• Keep track of the distance while traversing the tree.

• Return the values of nodes at distance K in any order.

The problem involves dividing an array into K subsets with equal sum.

• Use backtracking to try all possible combinations of dividing the array into K subsets.

• Keep track of the sum of elements in each subset and check if they are equal to the target sum.

• Optimize the backtracking algorithm by pruning branches that cannot lead to a valid solution.

• Consider edge cases such as empty array, negative numbers, and unequal division of elements.

• Ensure that the sum of all elements in the a...read more

Find pairs in a sorted doubly-linked list whose sum equals a given integer 'X'.

• Traverse the list from both ends to find pairs with sum equal to 'X'.

• Use two pointers approach to efficiently find the pairs.

• Handle cases where the sum is less than, equal to, or greater than 'X'.

Find the sum of the subarray with the maximum sum among all subarrays in an array of integers.

• Iterate through the array and keep track of the maximum sum subarray seen so far.

• At each index, decide whether to include the current element in the subarray or start a new subarray.

• Update the maximum sum subarray if a new maximum is found.

• Consider edge cases like all negative numbers in the array.

• Example: For input N=5, arr=[-2, 1, -3, 4, -1], the output is 4.

Determine the maximum number of roads that can be removed while ensuring a path exists for every pair of cities for two-wheeler and four-wheeler vehicles.

• Identify the type of road (two-wheeler, four-wheeler, or both) and its impact on the connectivity between cities.

• Consider the constraints provided in the input to optimize the solution.

• Remove roads strategically to maximize the number of roads removed while maintaining connectivity.

• If not all cities can be reached, return -1...read more

The goal is to minimize the difference between the maximum and minimum elements of an array by adjusting each element by a given value.

• Iterate through each test case and calculate the minimum possible difference between the maximum and minimum elements after modifications.

• For each element in the array, consider increasing or decreasing it by the given value K to minimize the overall difference.

• Return the calculated minimum difference for each test case.

The task is to find the smallest number greater than the given number, using the same set of digits.

• Iterate from right to left to find the first digit that can be swapped with a smaller digit on its right.

• Swap this digit with the smallest digit on its right that is greater than it.

• Sort the digits to the right of the swapped digit in ascending order to get the smallest number.

• If no such digit is found, return -1.

• Example: For '56789', swap '8' with '9' to get '56798'.

The task is to find all possible paths for a rat to navigate through a maze from start to finish.

• Use backtracking algorithm to explore all possible paths in the maze.

• Keep track of visited cells to avoid infinite loops.

• Generate paths by moving in all possible directions (up, down, left, right) until reaching the destination.

• Return the list of valid paths sorted in alphabetical order.

The minimum number of platforms needed at a railway station to avoid train waiting times is determined based on arrival and departure times.

• Sort the arrival and departure times in ascending order.

• Iterate through the times and keep track of the number of platforms needed at any given time.

• Update the minimum number of platforms needed as you iterate through the times.

• Return the minimum number of platforms needed.

Identify all prime numbers less than or equal to a given positive integer N.

• Iterate from 2 to N and check if each number is prime

• Use the Sieve of Eratosthenes algorithm for efficient prime number identification

• Optimize by only checking up to the square root of N for divisors

To maximize stock trading profit, find maximum profit achievable by buying and selling shares multiple times.

• Iterate through the array of stock prices and find all increasing sequences of prices.

• Calculate profit by buying at the start of each increasing sequence and selling at the end.

• Sum up all profits to get the maximum profit achievable.

The minimum depth of a Binary Tree is the number of nodes along the shortest path from the root node to the nearest leaf node.

• Traverse the Binary Tree using BFS (Breadth First Search) to find the minimum depth

• Keep track of the level of each node while traversing

• Stop the traversal as soon as a leaf node is encountered and return the level as the minimum depth

The problem involves updating and calculating the sum of elements in an array based on given operations.

• Implement update(l, r, val) to add (val + i) to arr[l + i] for all i in range [0, r - l].

• Implement rangeSum(l, r) to return the sum of elements in the array from index l to r.

• Handle queries using 1-based indexing and output the sum of arr[l..r] for each rangeSum operation.

To find the K-th smallest element in a BST, perform an in-order traversal and return the K-th element encountered.

• Perform in-order traversal of the BST to get elements in increasing order

• Keep track of the count of elements visited and return the K-th element

• Time complexity can be optimized by maintaining a count of nodes in each subtree

A website similar to Instagram for travelers, allowing users to share photos and stories from their trips.

• Include features like geotagging to show where photos were taken

• Allow users to create travel itineraries and share tips with others

• Implement a rating system for destinations and accommodations

• Enable users to connect with fellow travelers and plan trips together

Implement two stacks in a single array using two different approaches

• Divide the array into two halves and use one half for each stack

• Use two pointers, one for each stack, and move them towards each other as elements are pushed or popped

• Consider edge cases like stack overflow and underflow

SQL is a traditional relational database management system, while NoSQL is a non-relational database system.

• SQL is structured, uses tables with predefined schema, and is good for complex queries.

• NoSQL is unstructured, uses collections or documents, and is good for large amounts of data with simple queries.

• SQL is ACID compliant, ensuring data integrity, while NoSQL is BASE (Basically Available, Soft state, Eventually consistent) for scalability and flexibility.

• Examples of SQL ...read more

Reverse a linked list recursively by swapping pointers

• Start by checking if the current node is null or the next node is null

• If so, return the current node as it is the new head of the reversed list

• Otherwise, recursively call the function on the next node and swap pointers