Update

problems/0070.爬楼梯完全背包版本.md

@@ -186,6 +186,20 @@ func climbStairs(n int) int {
 }
 ```
 
+JavaScript:
+```javascript
+var climbStairs = function(n) {
+    const dp = new Array(n+1).fill(0);
+    const weight = [1,2];
+    dp[0] = 1;
+    for(let i = 0; i <= n; i++){ //先遍历背包
+        for(let j = 0; j < weight.length; j++){ // 再遍历物品
+            if(i >= weight[j]) dp[i] += dp[i-weight[j]];
+        }
+    }
+    return dp[n];
+};
+```
 
 
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