02. Average Student Grades

#include <iostream>
#include <string>
#include <queue>
#include <map>

using namespace std;

int main() {
    int n;
    cin >> n;

    map<string, queue<double>> students;

    string student;
    double grade;

    for (size_t i = 0; i < n; i++) {
        cin >> student;
        cin >> grade;
        students[student].push(grade);
    }

    for (auto i = students.begin(); i != students.end(); i++) {
        double sumGrades = 0;

        cout << i->first << " ->";

        int count = i->second.size();

        while (i->second.size() != 0) {
            printf(" %.2f", i->second.front());
            sumGrades += i->second.front();
            i->second.pop();
        }
        printf(" (avg: %.2f)\n", sumGrades / count);
    }

    return 0;
}