数据结构之单链表

单链表属于线性表的一种，不过与顺序表相比，线性单链表没有空间的限制，往往可以无限开辟空间并使用(除非内存不足)。但正是因为如此，在进行链表的插入、删除、等操作时，也比顺序结构的链表更为复杂，效率也不及顺序表，即时间复杂度高。

链表的节点结构如图:

链表结构:

以下是代码:

头文件List.h

#ifndef _LIST_H#define _LIST_H#include<iostream>#include<assert.h>using namespace std;#define ElemType inttypedef struct Node{ElemType data;struct Node *next;}Node, *PNode;typedef struct List{PNode first;PNode last;size_t size;}List;//////////////////////////////////////void InitList(List *list);bool push_back(List *list, ElemType x);bool push_front(List *list, ElemType x);bool pop_back(List *list);bool pop_front(List *list);Node* Find(List *list, ElemType key);bool delete_val(List *list, ElemType key);void ShowList(List *list);void clear(List *list);void destroy(List *list);bool resver(List *list);bool insert_val(List *list,ElemType key);ElemType getvalue(List *list,int x);bool modify(List *list,ElemType item,ElemType nitem);bool sort(List *list);int length(List *list);ElemType next(List *list,ElemType key);ElemType prio(List *list,ElemType key);#endif

各种函数实现List.cpp:

#include"List.h"void InitList(List *list){Node *s = (Node *)malloc(sizeof(Node));assert(s != NULL);s->next = NULL;list->first = list->last = s;list->size = 0;}bool push_back(List *list, ElemType x){Node *s = (Node*)malloc(sizeof(Node));if(s == NULL)return false;s->data = x;s->next = NULL;list->last->next = s;list->last = s;list->size++;return true;}bool push_front(List *list, ElemType x){Node *s = (Node *)malloc(sizeof(Node));if(s == NULL)return false;s->data = x;s->next = list->first->next;list->first->next = s;if(list->size == 0){list->last = s;}list->size++;return true;}void ShowList(List *list){Node *p = list->first->next;while(p != NULL){cout<<p->data<<"-->";p = p->next;}cout<<"Nul"<<endl;}bool pop_back(List *list){if(list->size == 0)return false;Node *pre = list->first;while(pre->next != list->last)pre = pre->next;pre->next = NULL;free(list->last);list->last = pre;list->size--;return true;}bool pop_front(List *list){if(list->size == 0)return false;Node *p = list->first->next;if(list->size == 1){free(p);list->first->next = NULL;list->last = list->first;}else{list->first->next = p->next;free(p);}list->size--;return true;}Node* Find(List *list, ElemType key)//若找到，返回该节点前一节点的地址{Node *p = list->first;while(p->next->next!=NULL && p->next->data!=key)p = p->next;if (p->next==list->last&&p->next->data!=key){return NULL;}return p;}bool delete_val(List *list, ElemType key){Node *p = Find(list,key);if(p == NULL){cout<<"该值不存在!"<<endl;return false;}Node *s=p->next;p->next=s->next;free(s);return true;}void clear(List *list){Node *p = list->first->next;while(p != NULL){list->first->next = p->next;free(p);p = list->first->next;}list->last = list->first;list->size = 0;}void destroy(List *list){clear(list);free(list->first);list->first = list->last = NULL;}bool insert_val(List *list,ElemType key){Node *s=(Node *)malloc(sizeof(Node));if (s==NULL){return false;}s->data=key;if (list->size==0){list->first->next=s;list->last->next=s;s->next=NULL;}else{Node *p=list->first;while (p->next!=NULL&&p->next->data<key){p=p->next;}s->next=p->next;p->next=s;}list->size++;return true;}ElemType getvalue(List *list,int x){if (list->size==0||x<1||x>list->size){return -1;}Node *p=list->first;for (int i=0;i<x;i++){p=p->next;}return p->data;}bool modify(List *list,ElemType item,ElemType nitem)//如何精简？{if (list->size==0){return false;}Node *p=list->first;Node *s=(Node *)malloc(sizeof(Node));s->data=nitem;if (p->next->data==item){s->next=p->next->next;free(p->next);p->next=s;}while (p->next->next!=NULL&&p->next->data!=item){p=p->next;}if (p->next==list->last){if (p->next->data==item){s->next=NULL;free(p->next);p->next=s;list->last=s;return true;}return false;}s->next=p->next->next;free(p->next);p->next=s;return true;/*if (list->size==0)//应用改变指针的方法来修改{return false;}Node *p=list->first;while (p->next!=NULL&&p->data!=item){p=p->next;}if (p==list->last){if (p->data==item){p->data=nitem;}return false;}p->data=nitem;return true;*/}bool sort(List *list){if (list->size==0||list->size==1){return false;}Node *p=list->first;for (;p->next!=NULL;p=p->next){for (Node *q=p->next;q->next!=NULL;){if (p->next->data>q->next->data){Node *ptmp=q->next;q->next=ptmp->next;ptmp->next=q;p->next=ptmp;/*ElemType tmp=p->next->data;p->next->data=p->next->next->data;p->next->next->data=tmp;*/}}}return true;}bool resver(List *list){if (list->size==0||list->size==1){return false;}Node *fp=list->first->next;Node *p=fp->next;Node *lp=p->next;fp->next=NULL;list->last->next=fp;if (lp!=NULL){do {p->next=fp;fp=p;p=lp;lp=lp->next;}while(p->next!=NULL);list->first->next=fp;}else{list->first->next=p;p->next=fp;}return true;}int length(List *list){return list->size;}ElemType next(List *list,ElemType key){if (list->size==0||list->size==1){return -1;}Node *p=list->first;while (p->next!=NULL){if (p->next->data==key&&p->next->next!=NULL){p=p->next;return p->next->data;}p=p->next;}return -1;}ElemType prio(List *list,ElemType key){if (list->size==0||list->size==1){return -1;}Node *p=list->first;if (p->next->data==key){return -1;}while (p->next!=NULL){if (p->next->data==key){return p->data;}p=p->next;}return -1;}

最后是主函数main.cpp:

#include"List.h"//#include<vld.h>void main(){List mylist;InitList(&mylist);int select = 1;ElemType item,nitem;Node *p = NULL;int pos;while(select){cout<<"**********************************"<<endl;cout<<"* [1] push_back   [2] push_front *"<<endl;cout<<"* [3] show_seqlist[0] quit_system*"<<endl;cout<<"* [4] pop_back    [5] pop_front  *"<<endl;cout<<"* [6] insert_pos  [7] insert_val *"<<endl;cout<<"* [8] delete_pos  [9] delete_val *"<<endl;cout<<"* [10] find       [11]getvalue   *"<<endl;cout<<"* [12] modify     [13]clear      *"<<endl;cout<<"* [14] destroy    [15]sort       *"<<endl;cout<<"* [16] resver     [17]length     *"<<endl;cout<<"* [18] next       [19]prio       *"<<endl;cout<<"**********************************"<<endl;cout<<"请选择:>";cin>>select;switch(select){case 1:cout<<"请输入要插入的数据(-1结束):>";while(cin>>item,item!=-1){push_back(&mylist,item);}break;case 2:cout<<"请输入要插入的数据(-1结束):>";while(cin>>item,item!=-1){push_front(&mylist,item);}break;case 3:ShowList(&mylist);break;case 4:pop_back(&mylist);break;case 5:pop_front(&mylist);break;case 6:break;case 7:cout<<"请输入要插入的值:>";cin>>item;insert_val(&mylist,item);break;case 8:break;case 9:cout<<"请输入要删除的值:>";cin>>item;delete_val(&mylist,item);break;case 10:cout<<"请输入要查找的值:>";cin>>item;p = Find(&mylist,item);if (p!=NULL){cout<<"该值是:"<<p->next->data<<endl;}else{cout<<"该值不存在!"<<endl;}break;case 11:cout<<"请输入要查找的值的序号:>";cin>>item;cout<<getvalue(&mylist,item)<<endl;break;case 12:///////////////cout<<"请输入要修改的值:>";cin>>item;cout<<"请输入要新的值:>";cin>>nitem;modify(&mylist,item,nitem);break;case 13:clear(&mylist);break;case 14:destroy(&mylist);break;case 15://///////////ERROR!sort(&mylist);break;case 16:////////////ERRORresver(&mylist);break;case 17:cout<<length(&mylist)<<endl;break;case 18:cout<<"请输入一个值:";cin>>item;cout<<next(&mylist,item)<<endl;break;case 19:cout<<"请输入一个值:";cin>>item;cout<<prio(&mylist,item)<<endl;break;default:break;}}destroy(&mylist);}