138.复制带随机指针的链表.java

/*
 * @lc app=leetcode.cn id=138 lang=java
 *
 * [138] 复制带随机指针的链表
 */

// @lc code=start
/*
// Definition for a Node.
class Node {
    int val;
    Node next;
    Node random;

    public Node(int val) {
        this.val = val;
        this.next = null;
        this.random = null;
    }
}
*/

/*
// Definition for a Node.
class Node {
    int val;
    Node next;
    Node random;

    public Node(int val) {
        this.val = val;
        this.next = null;
        this.random = null;
    }
}
*/

class Solution {
    public Node copyRandomList(Node head) {
        
        if(head==null){
            return head;
        }
        
        Map<Node,Node> map=new HashMap<>();
        Node cur=head;
        while(cur!=null){
            map.put(cur,new Node(cur.val));
            cur=cur.next;
        }
        
        cur=head;
        while(cur!=null){
            map.get(cur).next=map.get(cur.next);
            map.get(cur).random=map.get(cur.random);
            cur=cur.next;
        }
        
        return map.get(head);
  
    }
}
// @lc code=end