Create 0219-contains-duplicate-ii.swift

swift/0219-contains-duplicate-ii.swift

@@ -0,0 +1,21 @@
+/**
+ * Question Link: https://leetcode.com/problems/contains-duplicate-ii/
+ */
+
+ class Solution {
+    func containsNearbyDuplicate(_ nums: [Int], _ k: Int) -> Bool {
+        var hashset = Set<Int>()
+        var l = 0
+        for r in 0..<nums.count {
+            if r - l > k {
+                hashset.remove(nums[l])
+                l += 1
+            }
+            if hashset.contains(nums[r]) {
+                return true
+            }
+            hashset.insert(nums[r])
+        }
+        return false
+    }
+}