feat(leetcode): add No.219

Author: mickey0524

219.Contains-Duplicate-II.java

@@ -0,0 +1,23 @@
+// https://leetcode.com/problems/contains-duplicate-ii/
+//
+// algorithms
+// Easy (36.55%)
+// Total Accepted: 234,075
+// Total Submissions: 640,395
+
+
+class Solution {
+    public boolean containsNearbyDuplicate(int[] nums, int k) {
+        HashMap<Integer, Integer> map = new HashMap<>();
+        int len = nums.length;
+
+        for (int i = 0; i < len; i++) {
+            if (map.containsKey(nums[i]) && i - map.get(nums[i]) <= k) {
+                return true;
+            }
+            map.put(nums[i], i);
+        }
+
+        return false;
+    }
+}