coin循環要在外面 從小到大 不會有重復

 1 class Solution {
 2     public int change(int amount, int[] coins) {
 3         // if(coins.length == 0) return 1;
 4         int[] dp = new int[amount + 1];
 5         dp[0] = 1;
 6         Arrays.sort(coins);
 7         for(int j = 0; j < coins.length; j++){
 8             for
 
(int i = 1; i <= amount; i++){
 9                 if(coins[j] <= i){
10                     dp[i] += dp[i - coins[j]];
11                 }
12             }
13         }
14         return dp[amount];
15         
16     }
17 }

518. Coin Change 2