contains duplicate

Author: bunu23

easy/contains-duplicate/Solution.java

@@ -0,0 +1,12 @@
+class Solution {
+    public boolean containsDuplicate(int[] nums) {
+        HashSet<Integer> seenNumber = new HashSet<>();
+        for (int num : nums) {
+            if (seenNumber.contains(num)) {
+                return true;
+            }
+            seenNumber.add(num);
+        }
+        return false;
+    }
+}