复杂链表的复制

/*
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;
        RandomListNode p = pHead;
        while (p != null) {
            RandomListNode node = new RandomListNode(p.label);
            node.next = p.next;
            p.next = node;
            p = node.next;
        }
        p = pHead.next;
        RandomListNode last = pHead;
        while (p != null) { // 可能random指向自己，或者一个不在链表中的结点
            p.random = last.random == null ? null : last.random.next;
            last = p.next;
            p = last == null ? null : last.next;
        }
        RandomListNode curHead = pHead.next;
        last = pHead;
        p = curHead;
        while (p!= null) {
            last.next = p.next;
            last = p.next;
            p.next = last == null ? null : last.next;
            p = p.next;
        }
        return curHead;
    }
}