题解 | #复杂链表的复制#

import java.util.*;
/*
public class RandomListNode {
    int label;
    RandomListNode next = null;
    RandomListNode random = null;

    RandomListNode(int label) {
        this.label = label;
    }
}
*/
public class Solution {
    public RandomListNode Clone(RandomListNode pHead) {
        if (pHead == null)
            return null;
        //第一步，在每个节点的后面插入复制的节点。
        RandomListNode cur = pHead;
        while (cur != null) {
            RandomListNode clone = new RandomListNode(cur.label);
            clone.next = cur.next;
            cur.next = clone;
            cur = clone.next;
        }
        //第二步，对复制节点的 random 链接进行赋值。
        cur = pHead;
        while (cur != null) {
            RandomListNode clone = cur.next;
            if (cur.random != null)
                clone.random = cur.random.next;
            cur = clone.next;
        }
        //第三步，拆分。
        cur = pHead;
        RandomListNode pCloneHead = pHead.next;
        while (cur.next != null) {
            RandomListNode next = cur.next;
            cur.next = next.next;
            cur = next;
        }
        return pCloneHead;
    }
}