add solution for clone-graph

Author: Hyeri1ee

clone-graph/Hyeri1ee.java

@@ -0,0 +1,48 @@
+import java.util.*;
+/*
+class Node {
+    public int val;
+    public List<Node> neighbors;
+    public Node() {
+        val = 0;
+        neighbors = new ArrayList<Node>();
+    }
+    public Node(int _val) {
+        val = _val;
+        neighbors = new ArrayList<Node>();
+    }
+    public Node(int _val, ArrayList<Node> _neighbors) {
+        val = _val;
+        neighbors = _neighbors;
+    }
+}
+*/
+
+
+class Solution {
+
+
+    //기존 node, 복사한 node
+    Map<Node, Node> visited = new HashMap<>();
+    public Node cloneGraph(Node node) {
+        if (node==null) return null;
+
+        if (visited.containsKey(node)){
+            return visited.get(node);
+        }
+
+        //없는 경우
+        Node newClone= new Node(node.val);
+        visited.put(node, newClone);
+
+        //이웃 복사
+        for(Node target : node.neighbors){
+            newClone.neighbors.add(cloneGraph(target));
+        }
+
+        return newClone;
+
+    }
+}
+
+