Goldman Sachs Associate Engineer Interview Questions and Answers

Q1. Find the missing number in the array? Array size is of n-1 and contains 1 to n numbers with 1 digit missing.
Ans. 
The missing number in the array can be found by calculating the sum of all numbers in the array and then subtracting it from the sum of numbers from 1 to n.
• Calculate the sum of all numbers in the array.

• Calculate the sum of numbers from 1 to n using the formula n*(n+1)/2.

• Subtract the sum of array from the sum of numbers from 1 to n to find the missing number.
Answered by AI
Add your answer
Q2. Find the number of parenthesis have to be removed to make it a valid parenthesis --> (())) - 1 has to be removed, ((() -> 2 has to be removed.
Ans. 
Count the number of parenthesis to be removed to make it valid.
• Iterate through the string and keep track of open and close parenthesis.

• If a close parenthesis is encountered without a corresponding open parenthesis, increment the count of removals.

• Return the total count of removals needed to make the string valid.
Answered by AI
Add your answer

Q1. Find the maximum sub-array having continues numbers(i,i+1,i+2..)
Ans. 
Find the maximum sub-array with continuous numbers
• Iterate through the array and keep track of the current sub-array sum

• Update the maximum sum and sub-array indices as you iterate

• Handle cases where the array contains negative numbers as well

• Example: Input array [2, 3, -4, 5, 7], maximum sub-array is [2, 3, -4, 5, 7]
Answered by AI
Add your answer
Q2. Number of islands variant - focused on time complexity
Ans. 
Count the number of islands in a 2D grid variant, focusing on time complexity.
• Use Depth First Search (DFS) or Breadth First Search (BFS) to traverse the grid and mark visited islands.

• Optimize by using Union Find data structure to keep track of connected islands.

• Time complexity can be O(m*n) where m is the number of rows and n is the number of columns.
Answered by AI
Add your answer

1st round was online coding test with 1 DSA problem and one OOPs based problem