HDU 2093(考试排名)解题纠错-优快云博客

本文链接：https://blog.youkuaiyun.com/logiciel/article/details/6703168

本文提供了一个使用C++进行竞赛编程的案例，包括学生和题目类的定义与实现，通过具体示例展示了如何处理学生答题情况及评分逻辑，并对代码中存在的问题进行了修正。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

#include <iostream>
#include <iomanip>
#include<algorithm>
#include <string>
#include <vector>
using namespace std;


class Problem
{
public:
    Problem();
    int GetGrade();
    static void SetPunish();

private:
    int accept_time;
    int wrong_times;
    static int punish;

};
Problem::Problem()
    {
        int temp;
        cin>>temp;
        if(temp<0)
        {
            this->wrong_times = -temp;
            this->accept_time = 0;
        }
        else
        {
            if(temp==0)
            {
                this->wrong_times = 0;
                this->accept_time = 0;
            }
            else
            {
                this->accept_time = temp;
                if( cin.get()=='(')
                {
                    cin>>this->wrong_times;
                    cin.get();
                }
                else
                {
                    this->wrong_times = 0;
                }
            }
        }
    }
int Problem::GetGrade()
{
    if( this->accept_time==0 )
    {
        return 0;
    }
    else
    {
        return this->accept_time + this->wrong_times * this->punish;
    }
}
void Problem::SetPunish()
{
    cin>>Problem::punish;
}


class Student
{
public:
    Student();
    void Calculate();
    int GetGrade();
    int GetAccept();
    string& GetName();
    void print();
    static void SetPeople();

private:
    string name;
    Problem *questions;
    int accept_problem;
    int grade;
    static int people;
};
Student::Student()
{
    cin>>this->name;
    this->questions = new Problem[this->people];
    this->Calculate();
}
inline string& Student::GetName()
{
    return this->name;
}

inline int Student::GetAccept()
{
    return this->accept_problem;
}
inline int Student::GetGrade()
{
    return this->grade;
}

void Student::Calculate()
{
    int i, grade;
    this->accept_problem = 0;
    this->grade = 0;
    for(i = 0; i < this->people; i++)
    {
        grade = this->questions[i].GetGrade();
        if( grade )
        {
            this->grade += grade;
            this->accept_problem += 1;
        }
    }
}
void Student::SetPeople()
{
    cin>>Student::people;
}
bool compare(Student &a,Student &b);
bool compare(Student &a,Student &b)
{
    if( a.GetAccept() < b.GetAccept() )
    {
        return false;
    }
    if( a.GetAccept() > b.GetAccept() )
    {
        return true;
    }
    if( a.GetGrade() < b.GetGrade() )
    {
        return true;
    }
    if( a.GetGrade() > b.GetGrade() )
    {
        return false;
    }
    if( a.GetName().compare( b.GetName() ) < 0 )
    {
        return true;
    }
    else
    {
        return false;
    }
}


void Student::print()
{
    cout<<setw(10)<<left<<this->GetName()<<" "<<right<<setw(2)<<this->GetAccept()<<" "<<right<<setw(4)\
        <<this->GetGrade()<<endl;
}

int Problem::punish = 0;
int Student::people = 0;
int main()
{
    Student *p;
    vector<Student>students;
    Student::SetPeople();
    Problem::SetPunish();
    while( cin.peek()!=EOF )
    {
        p = new Student();
        students.push_back(*p);
        cin.get();
    }
    sort(students.begin(),students.end(),compare);
    int i = students.size(),j;
    for(j = 0; j < i; j++)
    {
        students[j].print();
    }


    return 0;
}

设有以下输入：

1 20
Smith 10
John 20

John的第1个字符被该程序中cin.get()吃掉，变成了ohn。

另外，有时会多出1个数值全为0的记录。

问题出在cin.peek()!=EOF 这个条件，它不能及时地发挥作用。还是要判读入的人名是否为空。

还有，程序中的变量名people改为problem_number较为确切。

以下修改AC:

#include <iostream>
#include <iomanip>
#include<algorithm>
#include <string>
#include <vector>
using namespace std;


class Problem
{
public:
    Problem();
    int GetGrade();
    static void SetPunish();

private:
    int accept_time;
    int wrong_times;
    static int punish;

};
Problem::Problem()
    {
        int temp;
        char c;
        cin>>temp;
        if(temp<0)
        {
            this->wrong_times = -temp;
            this->accept_time = 0;
        }
        else
        {
            if(temp==0)
            {
                this->wrong_times = 0;
                this->accept_time = 0;
            }
            else
            {
                this->accept_time = temp;
                if( (c=cin.get())=='(')
                {
                    cin>>this->wrong_times;
                    cin.get();
                }
                else
                {
                    this->wrong_times = 0;
                }
            }
        }
    }
int Problem::GetGrade()
{
    if( this->accept_time==0 )
    {
        return 0;
    }
    else
    {
        return this->accept_time + this->wrong_times * this->punish;
    }
}
void Problem::SetPunish()
{
    cin>>Problem::punish;
}


class Student
{
public:
    Student();
    void Calculate();
    int GetGrade();
    int GetAccept();
    string& GetName();
    void print();
    static void SetPeople();

private:
    string name;
    Problem *questions;
    int accept_problem;
    int grade;
    static int people;
};
Student::Student()
{
    cin>>this->name;
    if (!this->name.empty())//加
    {
      this->questions = new Problem[this->people];
      this->Calculate();
    }
}
inline string& Student::GetName()
{
    return this->name;
}

inline int Student::GetAccept()
{
    return this->accept_problem;
}
inline int Student::GetGrade()
{
    return this->grade;
}

void Student::Calculate()
{
    int i, grade;
    this->accept_problem = 0;
    this->grade = 0;
    for(i = 0; i < this->people; i++)
    {
        grade = this->questions[i].GetGrade();
        if( grade )
        {
            this->grade += grade;
            this->accept_problem += 1;
        }
    }
}
void Student::SetPeople()
{
    cin>>Student::people;
}
bool compare(Student &a,Student &b);
bool compare(Student &a,Student &b)
{
    if( a.GetAccept() < b.GetAccept() )
    {
        return false;
    }
    if( a.GetAccept() > b.GetAccept() )
    {
        return true;
    }
    if( a.GetGrade() < b.GetGrade() )
    {
        return true;
    }
    if( a.GetGrade() > b.GetGrade() )
    {
        return false;
    }
    if( a.GetName().compare( b.GetName() ) < 0 )
    {
        return true;
    }
    else
    {
        return false;
    }
}


void Student::print()
{
    cout<<setw(10)<<left<<this->GetName()<<" "<<right<<setw(2)<<this->GetAccept()<<" "<<right<<setw(4)\
        <<this->GetGrade()<<endl;
}

int Problem::punish = 0;
int Student::people = 0;
int main()
{
    Student *p;
    vector<Student>students;
    Student::SetPeople();
    Problem::SetPunish();
    while( cin.peek()!=EOF )
    {
        p = new Student();
        if (!p->GetName().empty())//加
        students.push_back(*p);
        //删 cin.get();
    }
    sort(students.begin(),students.end(),compare);
    int i = students.size(),j;
    for(j = 0; j < i; j++)
    {
        students[j].print();
    }


    return 0;
}