劍指offer-複雜鏈表的複製(python和c++）

題目描述

輸入一個複雜鏈表（每個節點中有節點值，以及兩個指針，一個指向下一個節點，另一個特殊指針random指向一個隨機節點），請對此鏈表進行深拷貝，並返回拷貝後的頭結點。（注意，輸出結果中請不要返回參數中的節點引用，否則判題程序會直接返回空）

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++

/*
*解題思路：
*1、遍歷鏈表，複製每個結點，如複製結點A得到A1，將結點A1插到結點A後面；
*2、重新遍歷鏈表，複製老結點的隨機指針給新結點，如A1.random = A.random.next;
*3、拆分鏈表，將鏈表拆分爲原鏈表和複製後的鏈表
*/
/*
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]複製結點，插入到原結點後方
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]還原新結點的random指針
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;
}
 
};