solve contains-duplicate

Author: samcho0608

contains-duplicate/samcho0608.java

@@ -0,0 +1,16 @@
+import java.util.HashSet;
+
+class Solution {
+    // return: does any value appear more than once in the array
+    // Time Complexity: O(n)
+    // Space Complexity: O(n)
+    public boolean containsDuplicate(int[] nums) {
+        HashSet<Integer> uniqNums = new HashSet<>();
+
+        for(int num : nums) {
+            if(!uniqNums.add(num)) return true;
+        }
+
+        return false;
+    }
+}