需要注意的点：成绩排名为并列时的代码。
#include <iostream>
#include <algorithm>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
struct Student{
int id;
int grade[4]; //存放四个分数
}stu[2010];
int now = 0;
int rankId[100000000][4] = {
0};
char course[4] = {
'A', 'C', 'M', 'E'};
bool cmp(Student a, Student b){
return a.grade[now] > b.grade[now];
}
int main(int argc, char** argv) {
int stuId[2010];
int n, m;
cin >> n >> m;
//输入数据 学号+成绩
for(int i = 0; i < n; i++){
cin >> stu[i].id >> stu[i].grade[1] >> stu[i].grade[2] >> stu[i].grade[3];
stu[i].grade[0] = (stu[i].grade[1]+stu[i].grade[2]+stu[i].grade[3]);
}
//输入待查的学号
for(int i = 0; i < m; i++){
cin >> stuId[i];
}
//算出每个人每门成绩的排名
for(now = 0; now < 4; now++){
sort(stu, stu + n, cmp);
rankId[stu[0].id][now] = 1; //该同学该课为第一名
//其他同学排序；//考虑并列的情况
for(int i = 1; i < n; i++){
if(stu[i].grade[now] == stu[i-1].grade[now]){
//如果和上一名同学成绩一样，则为并列
rankId[stu[i].id][now] = rankId[stu[i-1].id][now];
} else {
rankId[stu[i].id][now] = i+1;
}
}
}
//查询
for(int i = 0; i < m; i++) {
if(rankId[stuId[i]][0] == 0){
cout << "N/A" << endl;
} else {
int k = 0;
for(int j = 0; j < 4; j++){
if(rankId[stuId[i]][j] < rankId[stuId[i]][k]){
k = j;
}
}
cout << rankId[stuId[i]][k] << " " << course[k] << endl;
}
}
return 0;
}