Product of Array Except Self solution

Author: kim-young

product-of-array-except-self/kimyoung.js

@@ -0,0 +1,18 @@
+var productExceptSelf = function (nums) {
+    let result = new Array(nums.length).fill(0); // create a result array of length num
+    let pre = 1, post = 1; // default to 1 
+
+    for (let i = 0; i < nums.length; i++) { // fill the result array with prefix (multiplication of left values)
+        result[i] = pre;
+        pre *= nums[i];
+    }
+    for (let i = nums.length - 1; i >= 0; i--) { // multiply the postfix (multiplication of right values) to the result array in their corresponding index
+        result[i] *= post;
+        post *= nums[i];
+    }
+
+    return result;
+};
+
+// time - O(n) iterate through the nums array twice - 2n, remove constant which ends up to be n
+// space - O(1) result array not part of space complexity