[mumunuu] WEEK 01 solutions

contains-duplicate/mumunuu.java

@@ -0,0 +1,28 @@
+import java.util.HashSet;
+import java.util.Set;
+
+
+class Solution {
+
+    /**
+     *
+     * Set 판단으로 O(n)
+     *
+     * */
+    public boolean containsDuplicate(int[] nums) {
+
+        Set<Integer> set = new HashSet<>();
+
+        for (int num : nums) {
+
+            boolean isAdded = set.add(num);
+
+            if (!isAdded) {
+                return true;
+            }
+        }
+
+        return false;
+
+    }
+}