Coin change

Array Dynamic Programming Breadth-First Search

48.0% acceptance

Jan 12, 2026

20833

540

You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money. Return the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1. You may assume that you have an infinite number of each kind of coin.

Solution

Rust

Time O(n²)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn coin_change(coins: Vec<i32>, amount: i32) -> i32 {
    let amount = amount as usize;
    let mut dp = vec![amount + 1; amount + 1];
    dp[0] = 0;
    
    for i in 1..=amount {
      for &coin in &coins {
        let coin = coin as usize;
        if coin <= i {
          dp[i] = dp[i].min(dp[i - coin] + 1);
        }
      }
    }
    
    if dp[amount] > amount {
      -1
    } else {
      dp[amount] as i32
    }
  }
}