剑指 Offer 35. 复杂链表的复制

请实现 copyRandomList 函数，复制一个复杂链表。在复杂链表中，每个节点除了有一个 next 指针指向下一个节点，还有一个 random 指针指向链表中的任意节点或者 null。

 

示例 1：

输入：head = [[7,null],[13,0],[11,4],[10,2],[1,0]]
输出：[[7,null],[13,0],[11,4],[10,2],[1,0]]
示例 2：

输入：head = [[1,1],[2,1]]
输出：[[1,1],[2,1]]
示例 3：

输入：head = [[3,null],[3,0],[3,null]]
输出：[[3,null],[3,0],[3,null]]
示例 4：

输入：head = []
输出：[]
解释：给定的链表为空（空指针），因此返回 null。
 

提示：

-10000 <= Node.val <= 10000
Node.random 为空（null）或指向链表中的节点。
节点数目不超过 1000 。

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/fu-za-lian-biao-de-fu-zhi-lcof
著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

/*
// 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;
        }
        Node curr = head;
        while(curr != null){
            Node copyNode = new Node(curr.val);
            copyNode.next = curr.next;
            curr.next = copyNode;
            curr = copyNode.next;
        }
        curr = head;
        while(curr != null && curr.next != null){
            Node tempNode = curr.next;
            if(curr.random != null){
                tempNode.random = curr.random.next;
            }else{
                tempNode.random = null;
            }
            curr = curr.next.next;
        }
        Node result = new Node(0);
        Node origin = head;
        curr = head.next;
        result.next = curr;
        while(curr != null && curr.next != null){
            origin.next = curr.next;
            origin = origin.next;
            curr.next = curr.next.next;
            curr = curr.next;
        }
        return result.next;
    }
}

 

看了题解，大佬解法，思路清晰。

/*
// 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 map = new HashMap();
        Node curr = head;
        while(curr != null){
            map.put(curr, new Node(curr.val));
            curr = curr.next;
        }
        curr = head;
        while(curr != null){
            map.get(curr).next = map.get(curr.next);
            map.get(curr).random = map.get(curr.random);
            curr = curr.next;
        }
        return map.get(head);
    }
}