LeetCode 322 Coin Change - Problem Statement

Solve LeetCode 322: Coin Change. You have coin denominations. Find the minimum number of coins to make a target amount, or return $-1$ if impossible. This is unbounded knapsack with a twist: reduce count instead of get the highest value.

Each coin has "value" 1 (the count). The transition uses $\min$ instead of $\max$. Think about what state you need. How do you track both which coins you have used and what amount remains?