链表基本操作

问题：

输入

输入数据只有一组，第一行有n+1个整数，第一个整数是这行余下的整数数目n，后面是n个整数。这一行整数是用来初始化列表的，并且输入的顺序与列表中的顺序相反，也就是说如果列表中是1、2、3那么输入的顺序是3、2、1。

第二行有一个整数m，代表下面还有m行。每行有一个字符串，字符串是“get”，“insert”，“delete”，“show”中的一种。如果是“get”或者“delete”，则其后跟着一个整数a，代表获得或者删除第a个元素；如果是“insert”，则其后跟着两个整数a和e，代表在第a个位置前面插入e；“show”之后没有整数。

输出

如果获取成功，则输出该元素；如果删除成功则输出“delete OK”；如果获取失败或者删除失败，则输出“get fail”以及“delete fail”。如果插入成功则输出“insert OK”，否则输出“insert fail”。如果是“show”则输出列表中的所有元素，如果列表是空的，则输出“link list is empty”。注：所有的双引号均不输出。

样例输入 Copy

3 3 2 1
21
show
delete 1
show
delete 2
show
delete 1
show
delete 2
insert 2 5
show
insert 1 5
show
insert 1 7
show
insert 2 5
show
insert 3 6
show
insert 1 8
show
get 2

样例输出 Copy

1 2 3
delete OK
2 3
delete OK
2
delete OK
Link list is empty
delete fail
insert fail
Link list is empty
insert OK
5
insert OK
7 5
insert OK
7 5 5
insert OK
7 5 6 5
insert OK
8 7 5 6 5
7

代码：

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<algorithm>
using namespace std;

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

typedef struct list{
    node *head;
}List;

void Add (List *plist,int a[]);
void Show(List *plist);
void Get(List *plist,int nun);
void Insert(List *plist, int t, int m); 
void Delete(List *plist,int t);

int n;
int main(){
    cin>>n;
    int a[100];
    for(int i= 1;i<=n;i++){
        cin>>a[i];
    }
    List list;
    list.head->next = NULL;//有头结点 
    Add(&list,a);
    int m;
    cin>>m;
    string s;
    int num1,num2,num3;
    while(m--){
        cin>>s;
        if(s=="get"||s=="delete"){
            cin>>num1;
        }else if(s=="insert"){
            cin>>num2>>num3;
        }
        if(s=="show"){
            Show(&list);
        }else if(s=="get"){
            Get(&list,num1);
        }else if(s=="insert"){
            Insert(&list,num2,num3);
        }else{
            Delete(&list,num1);
        }
    }
    return 0;
}

void Add (List *plist,int a[]){
    Node *p,*pre;
    pre = plist->head;
    for(int i=n;i>=1;i--){
        p = (node*)malloc(sizeof(node));
        p->data = a[i];
        p->next = NULL;
        pre->next=p;
        pre = p; 
    }
}


void Show(List *plist){
    Node *L;
    if(plist->head->next==NULL){
        cout<<"link list is empty"<<endl;
    }else{
        for (L = plist->head->next; L; L = L->next)
        {
            cout << L->data << " ";
        }
        cout<<endl;
    }
}

void Get(List *plist,int num){
    Node *L;
    if(plist->head->next==NULL){
        cout<<"get fail"<<endl;
    }
    int isfound = 0;
    int count = 0;
    for(L=plist->head->next;L;L=L->next){
        count++;
        if(count == num){
            cout<<L->data<<endl;
            isfound = 1; 
            break;
        }
    }
    if(isfound == 0){
        cout<<"get fail"<<endl;
    }
}


void Insert(List *plist,int t,int m){
    if(plist->head->next==NULL){
        if(t==1){
            Node *newp = (node *)malloc(sizeof(node));
            newp->data = m;
            newp->next = NULL;
            plist->head->next = newp;
            cout << "insert OK" << endl;
        }else{
            cout << "insert fail" << endl;
        }    
    }else{
        Node *p = plist->head;
        for(int i=1;i<=t-1;i++){
            p = p->next;
        }
        Node *newp = (node *)malloc(sizeof(node));
        newp->data = m;
        newp->next = p->next;
        p->next = newp;
        cout << "insert OK" << endl;
    }
}

void Delete(List *plist,int t){
    Node *p,*pre;
    int isdelete = 0;
    int count=0;
    for(pre=plist->head,p=plist->head->next;p;pre = p,p=p->next){
        count++;
        if(count==t){
            pre->next=p->next;
            free(p);
            cout<<"delete OK"<<endl;
            isdelete = 1;
            break;
        }
    }
    if(isdelete==0){
        cout<<"delete fail"<<endl;
    }
}