322 零钱兑换

https://leetcode.cn/leetbook/read/top-interview-questions-medium/xvf0kh/

cost: 24m36s

class Solution {
public:
    int coinChange(vector<int>& coins, int amount) {
        vector<int> dp(amount + 1, -1);
        dp[0] = 0;
        for (int i = 1; i <= amount; i++) {
            if (dp[i] != -1) {
                continue;
            }
            for (const int coin : coins) {
                if (i < coin) {
                    continue;
                }
                if (dp[i - coin] != -1) {
                    if (dp[i] == -1) {
                        dp[i] = dp[i - coin] + 1;
                    } else {
                        dp[i] = std::min(dp[i], dp[i - coin] + 1);
                    }
                }
            }
        }
        return dp[amount];
    }
};