add js solution for coin-change-2

problems/0518.零钱兑换II.md

@@ -243,6 +243,22 @@ func change(amount int, coins []int) int {
 }
 ```
 
+Javascript：
+```javascript
+const change = (amount, coins) => {
+    let dp = Array(amount + 1).fill(0);
+    dp[0] = 1;
+
+    for(let i =0; i < coins.length; i++) {
+        for(let j = coins[i]; j <= amount; j++) {
+            dp[j] += dp[j - coins[i]];
+        }
+    }
+
+    return dp[amount];
+}
+```
+
 
 
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