Merge pull request #1282 from xiaofei-2020/dp16

添加（0494.目标和.md）：增加typescript版本

problems/0494.目标和.md

@@ -351,6 +351,25 @@ const findTargetSumWays = (nums, target) => {
 };
 ```
 
+TypeScript：
+
+```typescript
+function findTargetSumWays(nums: number[], target: number): number {
+    const sum: number = nums.reduce((pre, cur) => pre + cur);
+    if (Math.abs(target) > sum) return 0;
+    if ((target + sum) % 2 === 1) return 0;
+    const bagSize: number = (target + sum) / 2;
+    const dp: number[] = new Array(bagSize + 1).fill(0);
+    dp[0] = 1;
+    for (let i = 0; i < nums.length; i++) {
+        for (let j = bagSize; j >= nums[i]; j--) {
+            dp[j] += dp[j - nums[i]];
+        }
+    }
+    return dp[bagSize];
+};
+```
+
 
 
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