clone graph using BFS

Author: fishercoder1534

Common/src/classes/UndirectedGraphNode.java

@@ -0,0 +1,12 @@
+package classes;
+
+import java.util.*;
+
+/**
+ * Created by fishercoder1534 on 9/30/16.
+ */
+public class UndirectedGraphNode {
+    public int label;
+    public List<UndirectedGraphNode> neighbors;
+    public UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); }
+}

MEDIUM/src/medium/CloneGraph.java

@@ -0,0 +1,32 @@
+package medium;
+
+import classes.UndirectedGraphNode;
+import java.util.*;
+
+/**
+ * Created by fishercoder1534 on 9/30/16.
+ */
+public class CloneGraph {
+
+    public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {
+        if(node == null) return node;
+
+        Map<Integer, UndirectedGraphNode> map = new HashMap();
+        Queue<UndirectedGraphNode> queue = new LinkedList();
+        UndirectedGraphNode root = new UndirectedGraphNode(node.label);
+        map.put(root.label, root);
+        queue.offer(node);//remember to offer the original input node into the queue which contains all the information
+        while(!queue.isEmpty()){
+            UndirectedGraphNode curr = queue.poll();
+            for(UndirectedGraphNode eachNode : curr.neighbors){
+                if(!map.containsKey(eachNode.label)){
+                    map.put(eachNode.label, new UndirectedGraphNode(eachNode.label));
+                    queue.offer(eachNode);
+                }
+                map.get(curr.label).neighbors.add(map.get(eachNode.label));
+            }
+        }
+        return root;
+    }
+
+}