title: 零钱兑换问题
abbrlink: 5

322零钱兑换问题

class Solution {
public:
    int coinChange(vector<int>& coins, int amount) {
        int max1 = amount + 1;
        vector<int> dp(amount+1,max1);
        dp[0] = 0;
        for (int i = 0; i < coins.size(); ++i)
        {
            for (int j = 1; j <= amount; ++j)
            {
                if (coins[i] <= j)
                {
                    dp[j] = min(dp[j], dp[j - coins[i]] + 1);
             }
            }
        }
        return dp[amount] != max1 ? dp[amount] : -1;
    }
};

class Solution {
public:
    int coinChange(vector<int>& coins, int amount) {
        vector<int> dp(amount + 1, INT_MAX);
        dp[0] = 0;
        for (int i = 0; i < coins.size(); i++) { // 遍历物品
            for (int j = coins[i]; j <= amount; j++) { // 遍历背包
                if (dp[j - coins[i]] != INT_MAX) { // 如果dp[j - coins[i]]是初始值则跳过
                    dp[j] = min(dp[j - coins[i]] + 1, dp[j]);
                }
            }
        }
        if (dp[amount] == INT_MAX) return -1;
        return dp[amount];
    }
};