剑指offer-复杂链表的复制(python和c++）

题目描述

输入一个复杂链表（每个节点中有节点值，以及两个指针，一个指向下一个节点，另一个特殊指针random指向一个随机节点），请对此链表进行深拷贝，并返回拷贝后的头结点。（注意，输出结果中请不要返回参数中的节点引用，否则判题程序会直接返回空）

思路：

python

# -*- coding:utf-8 -*-
# class RandomListNode:
#     def __init__(self, x):
#         self.label = x
#         self.next = None
#         self.random = None
class Solution:
    # 返回 RandomListNode
    def Clone(self, pHead):
        # write code here
        if not pHead:
            return None
        cur = pHead
        while cur:
            tmp = RandomListNode(cur.label)
            tmp.next = cur.next
            cur.next = tmp
            cur = tmp.next
        cur = pHead
        while cur:
            tmp = cur.next
            if cur.random:
                tmp.random = cur.random.next
            cur = tmp.next
        cur = pHead
        res = pHead.next
        while cur.next:
            tmp = cur.next
            cur.next = tmp.next
            cur = tmp
        return res 

c++

/*
*解题思路：
*1、遍历链表，复制每个结点，如复制结点A得到A1，将结点A1插到结点A后面；
*2、重新遍历链表，复制老结点的随机指针给新结点，如A1.random = A.random.next;
*3、拆分链表，将链表拆分为原链表和复制后的链表
*/
/*
struct RandomListNode {
    int label;
    struct RandomListNode *next, *random;
    RandomListNode(int x) :
            label(x), next(NULL), random(NULL) {
    }
};
*/
class Solution {
public:
    RandomListNode* Clone(RandomListNode* pHead)
    {
        if (!pHead) return NULL;
    nodeClone(pHead);
    connectRandom(pHead);
    return reconnect(pHead);
    }
     
     
//[1]复制结点，插入到原结点后方
void nodeClone(RandomListNode *head)
{
    RandomListNode *pNode = head;
    while (pNode != NULL)
    {
        RandomListNode *pClone = new RandomListNode(pNode->label);
        pClone->next = pNode->next;
        pNode->next = pClone;
        pNode = pClone->next;
    }
}
 
//[2]还原新结点的random指针
void connectRandom(RandomListNode *head)
{
    RandomListNode *pNode = head;
     
    while (pNode != NULL)
    {
        RandomListNode *pClone = pNode->next;
        if (pNode->random)
        {
            pClone->random = pNode->random->next;
        }
        pNode = pClone->next;
    }
}
 
//[3]拆分
RandomListNode *reconnect(RandomListNode *head)
{
    RandomListNode *pNode = head;
    RandomListNode *result = head->next;
    while (pNode != NULL)
    {
        RandomListNode *pClone = pNode->next;
        pNode->next = pClone->next;
        pNode = pNode->next;
        if (pNode != NULL)
            pClone->next = pNode->next;
         
    }
    return result;
}
 
};