product of array expect self solution

Author: hoyeongkwak

product-of-array-except-self/hoyeongkwak.ts

@@ -0,0 +1,19 @@
+/*
+time complexity : O(n)
+space complexity : O(1)
+*/
+function productExceptSelf(nums: number[]): number[] {
+    const results = new Array(nums.length).fill(1) 
+    let before = 1
+    let after = 1
+    for (let i = 0; i < nums.length - 1; i++) {
+        before *= nums[i]
+        results[i + 1] *= before
+    }
+    for (let i = nums.length - 1; i > 0; i--) {
+        after *= nums[i]
+        results[i - 1] *= after
+    }
+
+    return results
+};