322. 零钱兑换

package leetcode;

import java.util.Arrays;

public class demo_322 {
    public int coinChange(int[] coins, int amount) {
        //目标为0，则对短长度为0
        if(amount==0) {return 0;}
        int[] dp=new int[amount+1];
        //数组中的全部值都为amount+1
        Arrays.fill(dp, amount+1);
        dp[0]=0;
        for(int i=1;i<=amount;i++) {
            //dp[i]=min{dp[i-coins[0]],dp[i-coins[1]]......dp[i-coins[n]]}+1
            for(int j=0;j<coins.length;j++) {
                if(i>=coins[j]) {
                    dp[i]=Math.min(dp[i], dp[i-coins[j]]+1);
                }
            }
        }
        //找不到子数组满足要求
        if(dp[amount]==amount+1) {return -1;}
        return dp[amount];
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        demo_322 demo_322=new demo_322();
        int[] coins= {1,2,5};
        System.out.println( demo_322.coinChange(coins, 11));
    }

}