CodingMediumcod-g137

Subject CombinatoricsLevel Mid–Senior~22 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given coin denominations and a target amount, count the number of distinct multisets of coins (order does not matter) that sum to the amount; each denomination may be used any number of times. Return the count. 1 <= len(coins) <= 6, amount <= 60, denominations are distinct positive integers.

Implement

count_coin_combinations(coins: list[int], amount: int) → int

Examples

in[[1,2,5],5]out4

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.