Update 494-target-sum.js

Author: everthis

494-target-sum.js

@@ -1,3 +1,36 @@
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number}
+ */
+const findTargetSumWays = function(nums, target) {
+    const sum = nums.reduce((a, b) => a+b);
+    
+    if(Math.abs(target) > sum) {
+        return 0;
+    }
+
+    if((target + sum) % 2) {
+        return 0;
+    }
+
+    const halfSum = (target + sum) / 2;
+
+    let dp = new Array(halfSum+1).fill(0);
+    dp[0] = 1;
+
+    for(let i = 0; i < nums.length; i++) {
+        for(let j = halfSum; j >= nums[i]; j--) {
+            dp[j] += dp[j - nums[i]];
+        }
+    }
+
+    return dp[halfSum];
+};
+
+
+// another
+
 /**
  * @param {number[]} nums
  * @param {number} S