feat: Add solution for LeetCode problem 238

Author: WhiteHyun

product-of-array-except-self/WhiteHyun.swift

@@ -0,0 +1,27 @@
+//  
+//  238. Product of Array Except Self
+//  https://leetcode.com/problems/product-of-array-except-self/description/
+//  Dale-Study
+//  
+//  Created by WhiteHyun on 2024/06/01.
+//  
+
+final class Solution {
+  func productExceptSelf(_ nums: [Int]) -> [Int] {
+    var answer: [Int] = .init(repeating: 1, count: nums.count)
+
+    var left_product = 1
+    for i in nums.indices {
+      answer[i] = left_product
+      left_product *= nums[i]
+    }
+
+    var right_product = 1
+    for i in nums.indices.reversed() {
+      answer[i] *= right_product
+      right_product *= nums[i]
+    }
+
+    return answer
+  }
+}