CodingMediumcod-g533

Subject KnapsackLevel Mid–Senior~20 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given an integer amount and a list of distinct positive coin denominations (unlimited supply of each), return the number of distinct combinations of coins that sum to exactly amount. Combinations are unordered, so {1,2} and {2,1} count once. Return 0 if it cannot be made; amount may be 0 (one way: use no coins).

Implement

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

Examples

in[5,[1,2,5]]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.