Merge pull request CyC2018#752 from gb145234/work

修改leetcode题解动态规划01背包问题第五题

Author: CyC2018

docs/notes/Leetcode 题解 - 动态规划.md

@@ -906,9 +906,6 @@ Explanation: there are four ways to make up the amount:
 
 ```java
 public int change(int amount, int[] coins) {
-    if (amount == 0 || coins == null || coins.length == 0) {
-        return 0;
-    }
     int[] dp = new int[amount + 1];
     dp[0] = 1;
     for (int coin : coins) {