Add file Copy_list_with_random_pointer.java

Author: tinycedar

Copy_list_with_random_pointer.java

@@ -0,0 +1,24 @@
+/**
+ * Definition for singly-linked list with a random pointer.
+ * class RandomListNode {
+ *     int label;
+ *     RandomListNode next, random;
+ *     RandomListNode(int x) { this.label = x; }
+ * };
+ */
+public class Copy_list_with_random_pointer {
+    public RandomListNode copyRandomList(RandomListNode head) {
+        if (head == null) {
+            return null;
+        }
+        Map<RandomListNode, RandomListNode> map = new HashMap<>();
+        for (RandomListNode n = head; n != null; n = n.next) {
+            map.put(n, new RandomListNode(n.label));
+        }
+        for (RandomListNode n = head; n != null; n = n.next) {
+            map.get(n).next = map.get(n.next);
+            map.get(n).random = map.get(n.random);
+        }
+        return map.get(head);
+    }
+}