Contains Duplicate

Author: forest000014

contains-duplicate/forest000014.java

@@ -0,0 +1,26 @@
+/*
+Runtime: 10 ms(Beats: 89.16 %)
+Time Complexity: O(n)
+- HashSet r/w : O(1)
+- nums iteration : ( O(1) + O(1) ) * n = O(n)
+
+Memory: 58.63 MB(Beats: 22.32 %)
+Space Complexity: O(n)
+*/
+
+
+class Solution {
+    public boolean containsDuplicate(int[] nums) {
+        Set<Integer> set = new HashSet<>();
+
+        for (int num: nums) {
+            if (set.contains(num)) {
+                return true;
+            }
+
+            set.add(num);
+        }
+
+        return false;
+    }
+}