题解 | #成绩排序#

#include<iostream>
#include<algorithm>
#include<vector>

struct Student
{
    int num;
    int grade;
    Student(int n, int g)
        : num(n), grade(g)
    {
    }   
};

bool compare(const Student& a, const Student& b)
{
    if(a.grade < b.grade)
    {
        return true;
    }else if(a.grade > b.grade)
    {
        return false;
    }

    return a.num < b.num;
}

int main()
{
    int n;
    std::cin >> n;
    std::vector<Student> students;
    students.reserve(n);//预先指定要分配的内存数量
    for(int i = 0;i < n;i++)
    {
        int p,q;
        std::cin >> p >> q;
        students.emplace_back(p, q);//直接传递参数，利用构造函数，而不是传递对象，避免复制加快执行速度
    }
    std::sort(students.begin(), students.end(), compare);
    for(Student student : students)
    {
        std::cout << student.num << " " << student.grade << "\n";
    }
}