contains duplicate

Author: delight010

contains-duplicate/delight010.swift

@@ -0,0 +1,13 @@
+class Solution {
+    func containsDuplicate(_ nums: [Int]) -> Bool {
+        var dictionary: [Int: Int] = [:]
+        for (index, num) in nums.enumerated() {
+            if let value = dictionary[num], value != index {
+                return true
+            }
+            dictionary[num] = index
+        }
+        return false
+    }
+}
+