leetcode518

 1 class Solution {  2     public int change(int amount, int[] coins) {  3         if (amount == 0) {  4             return 1;  5         }  6         if(coins == null || coins.length == 0){  7             return 0;  8         }  9         int[] dp = new int[amount + 1]; 10         dp[0] = 1; 11         for (int coin : coins) { 12             for (int i = coin; i <= amount; i++) { 13                 dp[i] += dp[i - coin]; 14             } 15         } 16         return dp[amount]; 17     } 18 }

对比leetcode322：

 1 public class Solution {  2     public int coinChange(int[] coins, int amount) {  3         if (amount == 0) return 0;  4         int[] dp = new int[amount + 1];  5         dp[0] = 0;  6         for (int i = 1;i <= amount ;i++ ) {  7             dp[i] = Integer.MAX_VALUE;  8             for(int k :coins) {  9                 if(i>=k && dp[i-k] != Integer.MAX_VALUE) { 10                     dp[i] = Math.min(dp[i-k] + 1,dp[i]); 11                 } 12             } 13         } 14         if(dp[amount]<Integer.MAX_VALUE && dp[amount] > 0) { 15             return dp[amount]; 16         } else { 17             return -1; 18         } 19  20     } 21 }