数据结构——单链表查询、逆序、排序

1、思维导图

2、查、改、删算法

//快慢排序法找中间值
int mid_link(Link_t *plink)
{
    Link_Node_t *pfast = plink->phead;
    Link_Node_t *pslow = pfast;
    int m = 0;
    while(pfast != NULL)
    {
        pfast = pfast->pnext;
        ++m;
        if(m % 2 == 0)
        {
            pslow = pslow->pnext;
        }
    }
    printf("%d\n",pslow->data);
    printf("%p\n",pslow);
        
}


//快慢排序法查询倒数第k个
Link_Node_t *recipe_link_count(Link_t *plink)
{
    Link_Node_t *pfast = plink->phead;
    Link_Node_t *pslow = pfast;
    int m = 0;
    int n;
    scanf("%d",&n);
    while(pfast != NULL && m < n)
    {
        pfast = pfast->pnext;
        m++;
    }
    while(pfast != NULL)
    {
        pfast = pfast->pnext;
        pslow = pslow->pnext;
    }
    //printf("%d\n",pslow->data);
    //printf("%p\n",pslow);
    return pslow;
}


//删除指定节点
int pop_point_node(Link_t *plink)
{
    int n;
    int m = 0;
    printf("选择删除节点：");
    scanf("%d",&n);
    Link_Node_t *p = plink->phead;
    Link_Node_t *pdel = NULL;
    Link_Node_t *ptmp = NULL;
    if(p == NULL)
    {
        return 0;
    }
    else if(p->data == n)
    {
        pdel = p;
        plink->phead = p->pnext;
    }
    else if(p != NULL)
    {
        while(p->data != n)
        {
            ptmp = p;
            p = p->pnext;
        }
        pdel = p;
        ptmp->pnext = pdel->pnext;
    }
            free(pdel);
    return 0;
}

3、单链表逆序

//链表逆序
int reverse_link(Link_t *plink)
{
    if(is_empty_link(plink))
        return 0;
    Link_Node_t *ptmp = plink->phead;
    Link_Node_t *pinsert = NULL;
    plink->phead = NULL;
    while(ptmp != NULL)
    {
        pinsert = ptmp;
        ptmp = ptmp->pnext;
        pinsert->pnext = plink->phead;
        plink->phead = pinsert;
    }
}

4、插入排序（从未排序部分取出一个元素，插入到已排序部分的正确位置）

void insert_sort_link(Link_t *plink)
{
    if(is_empty_link(plink) || 1 == plink->clen)
    {
        return;
    }
    Link_Node_t *ptmp = plink->phead->pnext;
    Link_Node_t *pinsert = NULL;
    Link_Node_t *p = NULL;
    plink->phead->pnext = NULL;
    while(ptmp != NULL)
    {
    pinsert = ptmp;
    ptmp = ptmp->pnext;
    if(pinsert->data <= plink->phead->data)
    {
        pinsert->pnext = plink->phead; //头插
        plink->phead = pinsert;
    }
    else
    {
        p = plink->phead;
       while(p->pnext != NULL && p->pnext->data < pinsert->data)
       {
           p = p->pnext;
       }
        pinsert->pnext = p->pnext;  //尾插
        p->pnext = pinsert;   
    }
    }
}

双向链表------插删查改：

#include<stdio.h>
#include"dlink.h"
#include<stdlib.h>

DLink_t *create_doulink()
{
    DLink_t *pdoulink = malloc(sizeof(DLink_t));
    if(NULL == pdoulink)
    {
        perror("fail creat");
        return NULL;
    }
    pdoulink->phead = NULL;
    pdoulink->clen = 0;
    pthread_mutex_init(&pdoulink->mutex,NULL);
    return pdoulink;
}

//判空
int is_empty_doulink(DLink_t *pdoulink)
{
    return NULL == pdoulink->phead;
}

//头插
int push_doulink_head(DLink_t *pdoulink,DataType data)
{
    DLink_Node_t *pnode = malloc(sizeof(DLink_Node_t));
    if(NULL == pnode)
    {
        perror("fail malloc");
        return -1;
    }
    pnode->ppre = NULL;
    pnode->pnext = NULL;
    pnode->data = data;
    
    if(is_empty_doulink(pdoulink))
    {
        pdoulink->phead = pnode;
    }
    else
    {
        pnode->pnext = pdoulink->phead;
        pdoulink->phead->ppre = pnode;
        pdoulink->phead = pnode;
    }
    pdoulink->clen++;
}

//遍历
void print_pdoulink(DLink_t *pdoulink,int flag)
{
    if(is_empty_doulink(pdoulink))
        return;
    DLink_Node_t *p = pdoulink->phead;
    if(flag)
    {
        while(p != NULL)
        {
            printf(" %d %s %d\n",p->data.id,p->data.name,p->data.score);
            p = p->pnext;
        }
    }
    else
    {
        while(p->pnext != NULL)
        {
            p = p->pnext;
        }
        while(p != NULL)
        {
            printf(" %d %s %d\n",p->data.id,p->data.name,p->data.score);
            p = p->ppre;
        }
    }
    
}

//尾插
int push_doulink_tail(DLink_t *pdoulink ,DataType data)
{
    DLink_Node_t *pnode = malloc(sizeof(DLink_Node_t));
    if(pnode == NULL)
    {
        perror("fail malloc");
        return -1;
    }
    pnode->data = data;
    pnode->ppre = NULL;
    pnode->pnext = NULL;
    if((is_empty_doulink(pdoulink)))
    {
        push_doulink_head(pdoulink,data);
        free(pnode);
    }
    else
    {
        DLink_Node_t *p = pdoulink->phead;
        while(p->pnext != NULL)
        {
            p = p->pnext;
        }
        p->pnext = pnode;
        pnode->ppre = p;
    }

}

//头删
int pop_head(DLink_t *pdoulink)
{
    if(is_empty_doulink(pdoulink))
    {
        return 0;
    }
    DLink_Node_t *p = pdoulink->phead;
    pdoulink->phead = p->pnext;
    if(p->pnext != NULL)
    {
        p->pnext->ppre = NULL;
    }
    free(p);
}

//尾删
int pop_tail(DLink_t *pdoulink)
{
    DLink_Node_t *p = pdoulink->phead;
    if(is_empty_doulink(pdoulink))
    {
        return 0;
    }
    else if(p->pnext == NULL)
    {
        pop_head(pdoulink);
    }
    else
    {
        while(p->pnext->pnext != NULL)
        {
            p = p->pnext;
        }
        free(p->pnext);
        p->pnext = NULL;
    }
}

//查找 name
DataType *find_dliink_data(DLink_t *pdoulink,char *data)
{
    if(is_empty_doulink(pdoulink))
        return NULL;
    DLink_Node_t *p = pdoulink->phead;
    while(p != NULL)
    {
        if(strcmp(p->data.name,data) == 0)
        {
            return &(p->data);
        }
        p = p->pnext;
    }
    return NULL;
}

//修改(根据name查找)
void update_dlink_data(DLink_t *pdoulink,char *old_data,char *new_data)
{
    if(is_empty_doulink(pdoulink))
        return;
    DLink_Node_t *p = pdoulink->phead;
    while(p != NULL)
    {
        if(strcmp(p->data.name,old_data) == 0)
        {
            strcpy(p->data.name,new_data);
            break;
        }
        p = p->pnext;
    }
    
}

//销毁

void destory_dlink(DLink_t *pdoulink)
{
        while(!(is_empty_doulink(pdoulink)))
        {
            pop_head(pdoulink);
        }
        free(pdoulink);
}