Merge pull request #1286 from xiaofei-2020/dp19

添加（0518.零钱兑换II.md）：增加typescript版本

problems/0518.零钱兑换II.md

@@ -274,6 +274,21 @@ const change = (amount, coins) => {
 }
 ```
 
+TypeScript：
+
+```typescript
+function change(amount: number, coins: number[]): number {
+    const dp: number[] = new Array(amount + 1).fill(0);
+    dp[0] = 1;
+    for (let i = 0, length = coins.length; i < length; i++) {
+        for (let j = coins[i]; j <= amount; j++) {
+            dp[j] += dp[j - coins[i]];
+        }
+    }
+    return dp[amount];
+};
+```
+
 
 
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