PAT甲级真题 1036 Boys vs Girls (25分) C++实现（感觉值15分吧）

本文介绍了一种算法，用于分析学生数据库中男性和女性学生的最高和最低成绩差异。通过读取输入文件，算法记录最低分男生和最高分女生的信息，并在最后输出两者之间的成绩差值。如果缺少某性别的学生数据，则输出相应的提示。

题目

This time you are asked to tell the difference between the lowest grade of all the male students and the highest grade of all the female students.
Input Specification:
Each input file contains one test case. Each case contains a positive integer N, followed by N lines of student information. Each line contains a student’s name, gender, ID and grade, separated by a space, where name and ID are strings of no more than 10 characters with no space, gender is either F (female) or M (male), and grade is an integer between 0 and 100. It is guaranteed that all the grades are distinct.
Output Specification:
For each test case, output in 3 lines. The first line gives the name and ID of the female student with the highest grade, and the second line gives that of the male student with the lowest grade. The third line gives the difference gradeF-gradeM. If one such kind of student is missing, output “Absent” in the corresponding line, and output “NA” in the third line instead.
Sample Input 1:
3
Joe M Math990112 89
Mike M CS991301 100
Mary F EE990830 95
Sample Output 1:
Mary EE990830
Joe Math990112
6
Sample Input 2:
1
Jean M AA980920 60
Sample Output 2:
Absent
Jean AA980920
NA

思路

用两组临时变量记录最低分男和最高分女信息，一个string存name+id，初始化为"Absent"；一个score存分数，分别初始化为101和-1；根据分数决定是否替换二者。

最后输出分数差值，或"NA"即可。

代码

#include <iostream>
using namespace std;

int main(){
    int n;
    cin >> n;
    string boyName = "Absent";
    string girlName = "Absent";
    int boyScore = 101; 
    int girlScore = -1; 
    for (int i=0; i<n; i++){
        string name, id;
        char gender;
        int grade;
        cin >> name >> gender >> id >> grade;
        if (gender=='M' && grade < boyScore){
            boyScore = grade;
            boyName = name + " " + id;
        }
        else if (gender=='F' && grade > girlScore){
            girlScore = grade;
            girlName = name + " " + id;
        }
    }
    cout << girlName << endl;
    cout << boyName << endl;
    if (girlScore==-1 || boyScore==101){
        cout << "NA" << endl;
    }
    else{
        cout << girlScore - boyScore << endl;
    }
    return 0;
}