Merge pull request #1287 from xiaofei-2020/dp21

添加（0377.组合总和Ⅳ.md）：增加typescript版本

problems/0377.组合总和Ⅳ.md

@@ -221,7 +221,27 @@ const combinationSum4 = (nums, target) => {
 };
 ```
 
+TypeScript：
+
+```typescript
+function combinationSum4(nums: number[], target: number): number {
+    const dp: number[] = new Array(target + 1).fill(0);
+    dp[0] = 1;
+    // 遍历背包
+    for (let i = 1; i <= target; i++) {
+        // 遍历物品
+        for (let j = 0, length = nums.length; j < length; j++) {
+            if (i >= nums[j]) {
+                dp[i] += dp[i - nums[j]];
+            }
+        }
+    }
+    return dp[target];
+};
+```
+
 Rust 
+
 ```Rust
 impl Solution {
     pub fn combination_sum4(nums: Vec<i32>, target: i32) -> i32 {