feat: add solution for Two Sum problem on LeetCode

Author: WhiteHyun

two-sum/WhiteHyun.swift

@@ -0,0 +1,31 @@
+//
+//  1. Two Sum.swift
+//  https://leetcode.com/problems/two-sum/description/
+//  Algorithm
+//
+//  Created by 홍승현 on 2024/04/26.
+//
+
+import Foundation
+
+final class LeetCode1 {
+  func twoSum(_ numbers: [Int], _ target: Int) -> [Int] {
+    let sortedNumbersWithIndex = numbers.enumerated().sorted { lhs, rhs in
+      lhs.element < rhs.element
+    }
+    var left = 0
+    var right = sortedNumbersWithIndex.endIndex - 1
+
+    while left < right {
+      let sum = sortedNumbersWithIndex[left].element + sortedNumbersWithIndex[right].element
+      if sum == target { break }
+      if sum < target {
+        left += 1
+      } else {
+        right -= 1
+      }
+    }
+
+    return [sortedNumbersWithIndex[left].offset, sortedNumbersWithIndex[right].offset]
+  }
+}