Merge pull request #48 from Nakul1404/main

Created Leetcode-219.cpp

Author: gantavyamalviya

CPP/Problems/Leetcode-219.cpp

@@ -0,0 +1,15 @@
+class Solution {
+ public:
+  bool containsNearbyDuplicate(vector<int>& nums, int k) {
+    unordered_set<int> seen;
+
+    for (int i = 0; i < nums.size(); ++i) {
+      if (!seen.insert(nums[i]).second)
+        return true;
+      if (i >= k)
+        seen.erase(nums[i - k]);
+    }
+
+    return false;
+  }
+};