UVA 12412 - A Typical Homework (a.k.a Shi Xiong Bang Bang Mang) 模拟题 不好怎么评价

好吧，为了选择一个合适的数据结构纠结了很久。。。。因为要查排名，然后就想到了Treap，然后发现自己的Treap的板子写的不好，于是把Treap用template改写了一遍，然后发现用不上.......

最后看的标程，感觉标程的写法还是很不错的，比较短，而且也不是很难理解，就是...每一次查rank都是从头扫一遍，复杂度几乎都是O（n）的，不过因为上限只有100，数据量也不算很大，也能过去。但是我想用更快的数据结构呀！教练！

WA了2发，发现是在&&和||的组合判断式的时候少打了括号，导致答案错误，因为&&的优先级比||高嘛

写一个模拟题练练手喽

#include <string>#include <algorithm>#include <cstring>#include <iostream>using namespace std;const string menu="Welcome to Student Performance Management System (SPMS).\n\n1 - Add\n2 - Remove\n3 - Query\n4 - Show ranking\n5 - Show Statistics\n0 - Exit\n\n",course[]={"Chinese", "Mathematics", "English", "Programming"};int choice,rev[1010],n,getrank(int);bool valid();void add(),rem(),que(),shw();struct Stu{    string name,SID;    int CID,s[5];}arr[1010];int main(){    ios_base::sync_with_stdio(false);    cout.setf(ios_base::fixed);    cout.precision(2);    cout<<menu;    while(cin>>choice&&choice){        if(choice==1)            add();        else if(choice==2)            rem();        else if(choice==3)            que();        else if(choice==4)            cout<<"Showing the ranklist hurts students' self-esteem. Don't do that.\n";        else            shw();        cout<<menu;    }    return 0;}bool valid(){    for(int i=0;i<n;++i)    if(!rev[i]&&arr[i].SID==arr[n].SID)        return false;    return true;}void add(){    cout<<"Please enter the SID, CID, name and four scores. Enter 0 to finish.\n";    while(cin>>arr[n].SID&&!(arr[n].SID.size()==1&&arr[n].SID[0]=='0')){        cin>>arr[n].CID>>arr[n].name;        arr[n].s[4]=0;        for(int i=0;i<4;++i)            cin>>arr[n].s[i],arr[n].s[4]+=arr[n].s[i];        if(valid())            ++n;        else            cout<<"Duplicated SID.\n";        cout<<"Please enter the SID, CID, name and four scores. Enter 0 to finish.\n";    }}void rem(){    cout<<"Please enter SID or name. Enter 0 to finish.\n";    string str;    int num=0;    while(cin>>str&&!(str.size()==1&&str[0]=='0')){        for(int i=0;i<n;++i)        if(!rev[i]&&(arr[i].SID==str||arr[i].name==str))            rev[i]=true,++num;        cout<<num<<" student(s) removed.\n";        num=0;        cout<<"Please enter SID or name. Enter 0 to finish.\n";    }}void que(){    cout<<"Please enter SID or name. Enter 0 to finish.\n";    string str;    while(cin>>str&&!(str.size()==1&&str[0]=='0')){        for(int i=0;i<n;++i)        if(!rev[i]&&(arr[i].SID==str||arr[i].name==str))            cout<<getrank(i)<<' '<<arr[i].SID<<' '<<arr[i].CID<<' '<<arr[i].name<<' '<<arr[i].s[0]<<' '<<arr[i].s[1]<<' '<<arr[i].s[2]<<' '<<arr[i].s[3]<<' '<<arr[i].s[4]<<' '<<(arr[i].s[4]/4.0+1E-5)<<endl;        cout<<"Please enter SID or name. Enter 0 to finish.\n";    }}void shw(){    cout<<"Please enter class ID, 0 for the whole statistics.\n";    int cid,total=0,s[4]{},sm[4]{},cnt[5]{};    cin>>cid;    for(int i=0,k=0;i<n;++i)    if(!rev[i]&&(!cid||arr[i].CID==cid)){        ++total;        k=0;        for(int j=0;j<4;++j){            if(arr[i].s[j]>=60)                ++sm[j],++k;            s[j]+=arr[i].s[j];        }        ++cnt[k];    }    for(int i=0;i<4;++i)        cout<<course[i]<<"\nAverage Score: "<<(total==0?00.00:s[i]*1.0/total+1E-5)<<"\nNumber of passed students: "<<sm[i]<<"\nNumber of failed students: "<<total-sm[i]<<endl<<endl;    cout<<"Overall:\nNumber of students who passed all subjects: "<<cnt[4]        <<"\nNumber of students who passed 3 or more subjects: "<<cnt[4]+cnt[3]        <<"\nNumber of students who passed 2 or more subjects: "<<cnt[4]+cnt[3]+cnt[2]        <<"\nNumber of students who passed 1 or more subjects: "<<cnt[4]+cnt[3]+cnt[2]+cnt[1]        <<"\nNumber of students who failed all subjects: "<<cnt[0]<<endl<<endl;}int getrank(int ind){    int ran=0;    for(int i=0;i<n;++i)    if(!rev[i]&&arr[i].s[4]>arr[ind].s[4])        ++ran;    return ran+1;}