数据结构 - 单链表

1.用头指针head（头指针）标示一个单链表，单链表中L表示头结点的地址，头结点的指针域指向第一个结点，头结点的数据域无意义，可存储结点的数量。(链栈不需要头结点)

2.判断链表为空 ：head ->next = NULL ;

3.指向头结点的尾结点，循环链表

4.单链表逆置，头插法

5.链表的尾插：定义指针，且指针总是指向链表末尾

6.单链表特点：

  1>逻辑关系相邻的元素在物理位置上可以不相邻  2>表中的元素只能顺序访问而不能随机访问  3>表的大小可以动态改变  4>插入删除等操作只需要修改指针而无需移动元素。

#include <stdio.h>#include <stdlib.h>#define TURE  (1)#define FALSE (0)typedef unsigned char Boolean;typedef struct List_node{    int   data;    struct List_node* next;    //还不存在别名}List_node;//struct List_node 的别名为List_nodetypedef List_node* List_head;List_node * Malloc(int size){    List_node *result = (List_head)malloc(size);    if(result == NULL){        printf("memery is full.\n");        exit(1);    }    return result;}//链表初始化  定义头指针 产生头结点 并让头指针只想头结点List_head init_list(void){    List_head lhead = NULL;    lhead = Malloc(sizeof(List_node));    lhead->data = 0;    lhead->next = NULL;    return lhead;}// 链表的销毁 1.先销毁所有结点内容 free(结点地址)//2.最后置空链表头指针*phead = NULL 故要传入头指针的地址pheadvoid disdory_list(List_head * phead){    List_node *p = NULL;    List_node *q = NULL;    if(phead == NULL || *phead == NULL)    {         return;    }    p = *phead;  //p为头指针 头结点的地址    while(p != NULL)    {        q = p;        p = p->next;        free(q);    }    *phead = NULL;}//链表的头插Boolean push_front(List_head head,int value){    List_node * node = NULL;    if(head == NULL)    {        return FALSE;    }    node = Malloc(sizeof(List_node));    node->data = value;    node->next = head->next;    head->next = node;    head->data++;    return TURE;}//链表的输出void print_List(List_head head){    // List_head p = head->next;    // while( p != NULL){    //   printf("%d ",p->data);    // p = p->next;    //}    //注意区分 p = head->next 其中p为地址head对应结点的指针域，    //为第二个结点的地址，    //head->data,head->next  (p = head->next)  p->data,p->next    List_node *p = NULL;    for( p = head->next; p != NULL ;p = p->next)    {        printf("%d ",p->data);    }     printf("\n");     printf("the length is %d\n",head->data);}//链表的尾插Boolean push_back(List_head head,int value){    List_node *node = NULL;    List_node *p = NULL;    if(head == NULL)    {        return FALSE;    }    p = head -> next;    node = Malloc(sizeof(List_node));    while(p->next != NULL)    {        p = p->next;    }    node->data = value;    node->next = NULL;    p->next = node;    head->data++;    return TURE;}//链表的头删Boolean delect_front(List_head head){    List_node *p = NULL;    if(head == NULL){        return FALSE;    }    p = head->next;    head->next = head->next->next;    //删除结点直接free即可    free(p);    head->data--;    return TURE;}//链表的尾删Boolean delect_back(List_head head){    List_node *p = NULL;    List_node *q = NULL;    if(head == NULL){        return FALSE;    }    p = head->next;    while( p->next->next != NULL)    {        p = p->next;    }    q = p;    p = p->next;    q ->next = NULL;    free(p);    head->data--;    return TURE;}//指定结点的删除Boolean delect_node(List_head head,int value){    List_node *p = NULL;    List_node *q = NULL;    if(head == NULL){        return FALSE;    }    p = head;    while( p != NULL && p->next != NULL)     {         if(p->next->data == value){              q = p->next;              p->next = p->next->next;              free(q);              head->data--;         }         p = p->next;     }    return TURE;}//制定值的地址 经过输出结点地址，然后作出对特定值结点地址的修改Boolean changeAddr_node(List_head head,int value){    List_node *p = NULL;    List_node *q = NULL;    List_node *pnode = NULL;    if(head == NULL){        return FALSE;    }    p = head;    while(p->next != NULL )    {        if(p->next->data == value){             q = p->next;             pnode = (List_node*)realloc(NULL                                         ,sizeof(List_node));             printf("%p\n",&pnode);             pnode->next = p->next->next;             pnode->data = value;             p->next = pnode;             free(q);             break;        }        p = p->next;    }    return TURE;}//链表的升序排序 在小数据本数据的后面插，在大于本数据的前面插List_node* sort_grow(List_head head){    int temp = 0;    List_node *p = NULL;    List_node *q = NULL;    List_node *ptr = NULL;    if(head == NULL){        return FALSE;    }    p = head->next;    head->next = NULL;    while(p != NULL){       temp = 0;       q=p;       p=p->next;       if(head->next == NULL)       {           head->next = q;           q->next = NULL;           ptr = head->next;           continue;       }//                                 \|/(插入node q)///////////////////////////////head -> big node1 -> big node2 -> NULL/////////////////////       if(ptr->data > q->data)       {              q->next = ptr;              head->next= q;              ptr = head->next;              continue;       }                                                       //        \|/(插入node q)////////////////////// head  ->  little node1  ->  little node2   ->  big node3 //////////       while( temp == 0){           if(ptr ->next != NULL && ptr->data < q->data && ptr->next->data >= q->data){               q->next = ptr->next;               ptr->next = q;               ptr = head->next;               temp ++;               break;           }else if(ptr->next == NULL && ptr->data <= q->data){                                                     //    \|/(插入 node q) ///////////////////////head -> little node1 ->little node2 ->  NULL////////////////////////////////               q->next = NULL;               ptr->next = q;               ptr = head->next;               temp ++;               break;           }           ptr = ptr->next;       }       if(temp == 1){           continue;       }    }    return head;}//链表的降序排序(升序链表的逆序)List_node * sort_low(List_head ghead){   List_node *p = NULL;   List_node *q = NULL;   if(ghead == NULL)   {       return FALSE;   }   p = ghead->next;   ghead->next = NULL;   while(p != NULL)   {       q = p;       p = p -> next;   //想让结点p后移向下一个结点，防止p的next改变       q->next = ghead->next;       ghead->next = q;       //p = p->next; 若将while中第二行写在此处，由于P Q两个结点是同一个结点，故修改了q结点的next,       //同时是的p结点的next值也发生改变   }   return ghead;}//删除多个List_node* movemore_node(List_head head,int left,int right)   //从第一个结点开始计算{    int count = 0;    int i = 0;    int j = 0;    if(head == NULL){        exit(1);    }    List_node *p = NULL;    List_node *q = NULL;    p = head->next;    for(i = 1;i < left-1; ++i){        if(p != NULL){            p = p->next;        }else{            printf("第%d个结点不存在\n",left);            return head;        }    }    q = p;    for(j = 0;j <=(right - left) + 1;++j){        if(q != NULL)        {            q = q->next;            count++;        }else{           p->next = NULL;           head->data -= (count-1);           printf("第%d个结点不存在\n",right);           return head;        }    }    p->next = q;    head->data -= ((right - left)+1);    return head;}int main(int ac,char ** av){    int i = 0,j = 0;    List_head head = NULL;    List_head ghead = NULL;    List_head lhead = NULL;    List_head mhead = NULL;    head = init_list();    for(i = 0;i < 10;++i)    {        push_front(head,rand() % 10);    }    for(j = 0;j < 5;++j)    {        push_back(head,rand() % 100);    }    print_List(head);    push_front(head,12);    print_List(head);    //delect_front(head);    delect_back(head);    delect_node(head,3);    print_List(head);    //changeAddr_node(head,9);    ghead = sort_grow(head);    print_List(ghead);    lhead = sort_low(ghead);    print_List(lhead);    mhead = movemore_node(lhead,5,7);  //从第一个结点开始，删除第4，5，6，个结点    print_List(mhead);    //disdory_list(&head);    return 0;}

单链表的逆置：

void reverse(NodeType *H){      Nodetype *p = NULL;      Nodetype *q = NULL;      p = H->next;      H->next = NULL;      while(p != NULL){            //p指向下一个元素            q=p;                p = p->next;             //防断链            q->next = H->next;            H->next = q;      }}

单链表的算法：连接两个递增的单链表l1,l2， 并让其递增排列,算法如下： //尾插案例  

void sort_link(Lnode *l,Lnode *l1){    Lnode *p = l->next;    Lnode *q = l1->next;    l->next = NULL;    Lnode *m = l;    free(l1);    while(p != NULL && q != NULL)    {        if(p->data >= q->data)        {            m->next = p;            p = p->next;        }else{            m->next = q;            q = q->next;        }        m = m->next;        m->next = NULL;    }    if(p == NULL)    {        m->next = q;    }else{        m->next = p;    }}