Gusto Coding Interview Questions
25 Gusto coding interview problems with full optimal solutions — 8 easy, 12 medium, 5 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Gusto interviewer values, and a FAQ section.
Showing 8 problems of 25
- #1easyfrequently asked
1. Two Sum
Find the two indices whose values sum to a target. Gusto uses this as a warm-up to see if you think in hash maps before brute force — they care about naming, clean early returns, and whether you'd write a test for the no-solution case.
- #20easyfrequently asked
20. Valid Parentheses
Check whether a string of brackets is properly nested and closed. Gusto asks this to test stack intuition and clean code — they want to see a minimal bracket map and early exits, not a sprawling switch statement.
- #21easycommonly asked
21. Merge Two Sorted Lists
Merge two sorted linked lists into one sorted list. Gusto uses this to test linked-list pointer discipline and to see if you reach for a dummy head node — the single trick that eliminates all the edge-case noise.
- #53easycommonly asked
53. Maximum Subarray
Find the contiguous subarray with the largest sum (Kadane's algorithm). Gusto asks this to see if you can articulate a greedy decision rule clearly — 'extend the current subarray or start fresh' — before writing a single line.
- #70easycommonly asked
70. Climbing Stairs
Count the number of distinct ways to reach the top of an n-step staircase taking 1 or 2 steps at a time. Gusto uses this to introduce dynamic programming — they want to see you recognise the Fibonacci recurrence and optimise from O(n) space to O(1).
- #121easycommonly asked
121. Best Time to Buy and Sell Stock
Find the maximum profit from a single buy-sell transaction. Gusto's payroll domain gives this a natural framing — think 'lowest payroll-cost day so far vs. current revenue day.' They want the greedy single-pass insight, not dynamic programming.
- #206easyfrequently asked
206. Reverse Linked List
Reverse a singly linked list in-place. Gusto uses this to test pointer manipulation fundamentals and to see whether candidates can articulate the three-variable dance (prev, curr, next) before touching the keyboard.
- #283easycommonly asked
283. Move Zeroes
Move all zeroes to the end of an array while preserving the relative order of non-zero elements, in-place. Gusto asks this to test the two-pointer write-cursor pattern and to see if you minimise unnecessary swaps.