单链表

链表是面试中一个重要的内容：

1 实现一个单链表的建立測长，打印 

#include "stdafx.h"
#include <iostream>
#include <stdio.h>
#include <string.h>
#include <conio.h> 
 //控制台输入输出

typedef struct student
{
    int data;
    struct student *next;
}node;

//建立单链表
node* create()
{
    node *head,*p,*s;
    int x, cycle = 1;
    head = (node *)malloc(sizeof(node));
    p = head;
    while(cycle)
    {
        std::cout<<"please input the data: ";
        std::cin>>x;
        std::cout<<std::endl;
        if(x != 0)
        {
            s = (node *)malloc(sizeof(node));
            s->data = x;
            p->next = s;
            p = s;
        }
        else
            cycle = 0;
    }
    head = head->next;
    p->next = NULL;
    return head;
}
//单链表測长
int length(node *head)
{
    int n = 0;
    node *p;
    p = head;
    while(p != NULL)
    {
        p = p->next;
        n++;
    }
    return n;
}
//单链表打印
void print(node *head)
{
    node *p;
    int n;
    n = length(head);
    std::cout<<"Now, These "<<n<<" records are: "<<std::endl;
    p = head;
    if(p != NULL)
    {
        while(p != NULL)
        {
            std::cout<<p->data<<" -> ";
            p = p->next;
        }
        std::cout<<std::endl;
    }
}


int _tmain(int argc, _TCHAR* argv[])
{
    node *head;
    head = create();
    print(head);
    return 0;
}

2 单链表删除结点

int delete(struct Node* x,struct Node* head){
    struct Node* p = head->next;
    struct Node* pre = head;
   if(pre->value == x->value)//推断是否和头部同样
   {
        head=x;
        head->next=p;
        return 0;
   }
    while(p!=NULL)
   {
        if(p->value == x->value){
            pre->next = p->next;
            free(p);
            return 1;
        }else{
            pre = p;
        }

        p = p->next;
    }

    return 0;
}

3 单链表的插入

int ListInsert(node
 *head,int num,node *new)
{
    node *pre=head;
    node *p=head->next;
    int i=0;
    if(num==0) //开头
    {
      head=new;
      head->next=pre;
      return 0;
    }
    while(p!=NULL) //中间
    {
       if(i=num)
       {
         pre->next=new;
         new->next=p;
         return 0;
       }
       pre=p;
       p=p->next;
       ++i;
    }
   if(p==NULL) //结尾
   {
      p=new;
      new->next=NULL;
      return 0;
   }
}

4链表排序

<span style="font-size:18px;">void sort(node *head)
{
   node *p1,*p2;
   p1=head;
   if(p1->next==NULL)
   {
     return;
   }
   while(p1)
   {
      p2=p1->next;
      while(p2)
      {
         if(p2->data < p1->data)
         {
            int temp=p1->data;
            p1->data=p2->data;
            p2->data=temp;
         }
         p2=p2->next;
      }
     p1=p1->next;
   }
}
</span>

5 对于链表我们能够仅仅遍历一次就能找到中间节点，方法。建立两个指针一个每次加1，还有一个每次加2，当当中一个到达末尾，还有一个则处于中间节点位置。