[juhui-jeong] WEEK 1 Solutions

contains-duplicate/juhui-jeong.java

@@ -0,0 +1,38 @@
+/*
+
+// 첫번째 풀이
+class Solution {
+    public boolean containsDuplicate(int[] nums) {
+        for (int i=0; i < nums.length; i++) {
+            for (int j=i+1; j < nums.length; j++) {
+                if (nums[i] == nums[j]) return true;
+            }
+        }
+        return false;
+    }
+}
+
+// 두번째 풀이
+class Solution {
+    public boolean containsDuplicate(int[] nums) {
+        Set set = new HashSet<Integer>();
+        for (int i=0; i < nums.length; i++) {
+            set.add(nums[i]);
+        }
+
+        if (set.size() != nums.length) return true;
+        return false;
+    }
+}
+
+*/
+
+class Solution {
+    public boolean containsDuplicate(int[] nums) {
+        Set<Integer> set = new HashSet<>();        
+        for (int i=0; i < nums.length; i++) {
+            if (!set.add(nums[i])) return true;
+        }
+        return false;
+    }
+}