From 7d8fd083608b286f4aa1422cdb857e9afda9362e Mon Sep 17 00:00:00 2001
From: aadil42 <77232799+aadil42@users.noreply.github.com>
Date: Tue, 15 Aug 2023 18:08:57 +0530
Subject: [PATCH] Create code.js

Added solution for target sum.

Submission Link: https://leetcode.com/problems/target-sum/submissions/1022046879/
---
 .../001. Target Sum/code.js                   | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 02. Algorithms/09. Dynamic Programming/001. Target Sum/code.js

diff --git a/02. Algorithms/09. Dynamic Programming/001. Target Sum/code.js b/02. Algorithms/09. Dynamic Programming/001. Target Sum/code.js
new file mode 100644
index 00000000..e98a1031
--- /dev/null
+++ b/02. Algorithms/09. Dynamic Programming/001. Target Sum/code.js	
@@ -0,0 +1,29 @@
+/** Recursion, memoization
+ * https://leetcode.com/problems/target-sum/
+ * 
+ * Time O(m*n) where n = nums.length and m = target;
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number}
+ */
+var findTargetSumWays = function(nums, target) {
+    
+    const cache = new Map();
+
+    function dfs(i, total) {
+        const key = i + "-" + total;
+        if(cache.has(key)) return cache.get(key);
+
+        if(i === nums.length) {
+            if(total === target) return 1;
+            return 0;
+        }
+
+        const result = (dfs(i + 1, total + nums[i]) + dfs(i + 1, total - nums[i])); 
+        cache.set(key, result);
+        return cache.get(key);
+        // return cache[i+"-"+total];
+    }
+
+    return dfs(0,0);
+};