feat: Add solution for LeetCode problem 217 Contains Duplicate

Author: WhiteHyun

best-time-to-buy-and-sell-stock/WhiteHyun.swift

@@ -0,0 +1,15 @@
+//
+//  217. Contains Duplicate.swift
+//  https://leetcode.com/problems/contains-duplicate/description/
+//  Algorithm
+//
+//  Created by 홍승현 on 2024/04/26.
+//
+
+import Foundation
+
+final class LeetCode217 {
+  func containsDuplicate(_ nums: [Int]) -> Bool {
+    Set(nums).count != nums.count
+  }
+}