单链表的面试题2

复制复杂链表
复杂链表：⼀个链表的每个节点，有⼀个指向next指针指向下⼀个节 点，还有⼀个random指针指向这个链表中的⼀个随机节点或者NULL
思路如下

头文件

#ifndef __LINK_LIST_H__
#define __LINK_LIST_H__
typedef int DataType;

#include <assert.h>
#include <stdlib.h>
#include <stdio.h>

typedef struct ComplexNode
{
    DataType _data;//数据域
    struct ComplexNode* _next;//指向下一个结点的指针
    struct ComplexNode *_random;//指向链表中随机的结点
}ComplexNode;
//定义一个复杂链表
//复杂链表的输出
void printfcomplex(ComplexNode *complexlist);
//复杂链表的复制
ComplexNode * copycomplexlist(ComplexNode * head);

功能函数

void printfcomplex(ComplexNode *complexlist)//复杂链表的输出
{
    ComplexNode * cur = NULL;
    cur = complexlist;
    while (cur)
    {
        if (cur->_random)
        {
            printf("[%d]->%d  ", cur->_data, cur->_random->_data);
        }
        else
        {
            printf("[%d]->%d ",cur->_data,NULL);
        }
        cur=cur->_next;
    }
    printf("\n"); 
}
//复杂链表的复制
ComplexNode * copycomplexlist(ComplexNode * head)
{
    ComplexNode *cur = NULL;
    ComplexNode *copy= NULL;
    ComplexNode *pre1= NULL;
    ComplexNode *pre2 = NULL;
    ComplexNode *tmp = NULL;
    ComplexNode *newnode = NULL;
    cur = head;
    //将当前结点拷贝一份，插入到当前结点的下一个位置
    while (cur)
    {
        ComplexNode *newnode = (ComplexNode*)malloc(sizeof(ComplexNode));
        newnode->_data = cur->_data;
        newnode->_next = cur->_next;
        cur->_next = newnode;
        newnode->_random = NULL;
        cur = cur->_next->_next;
    }
    //调整random 指针
    tmp = head;
    copy = head->_next;
    while (tmp!=NULL)//当tmp的最后一个结点为空时，不再赋值
    {
        copy->_random = tmp->_random->_next;
        tmp = copy->_next;
        if (tmp != NULL)//最后一次结点为空，不再让copy往后移动
        {
            copy = tmp->_next;
        }
    }
    //断开next指针
    pre1= head;
    pre2 = head->_next;
    newnode = head->_next;
    while (pre1)
    {
        pre1->_next = pre2->_next;
        pre1 = pre1->_next;
        if (pre1 != NULL)
        {
            pre2->_next = pre1->_next;
            pre2 = pre2->_next;
        }
    }
    return newnode;
}

测试函数

void test4()
{
    ComplexNode *head;
    ComplexNode*head1;
    ComplexNode *p1 = Buynewnode(1);//为每一个结点动态开辟内存
    ComplexNode *p2 = Buynewnode(2);
    ComplexNode *p3 = Buynewnode(3);
    ComplexNode *p4 = Buynewnode(4);
    head  = p1;
    p1->_next = p2;//为每一个结点的nest和random指向值
    p1->_random = p4;
    p2->_next = p3;
    p2->_random = p3;
    p3->_next = p4;
    p3->_random = p1;
    p4->_next = NULL;
    p4->_random = p2;
    printfcomplex(head);//复杂链表的输出
    head1=copycomplexlist(head);//复制单链表
    printfcomplex(head1);
}
int  main()
{
    test4();//测试复杂链表的复制
    return 0;
}

结果显示