CodingHardcod-g357

Subject BacktrackingLevel Senior–Staff~35 minCommon in Distributed systems · Algorithms & data structures interviewsIndustries Software development

Question

Given an array of integers matchsticks (length 1..15, each value 1..10^8), where each value is the length of a matchstick, determine whether you can use every matchstick exactly once, joining them end to end, to form a square (four sides of equal length). Matchsticks cannot be broken. Return a boolean.

Implement

makesquare(matchsticks: list[int]) → bool

Examples

in[[1,1,2,2,2]]outtrue

What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Learn the concepts

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.