PAT甲刷题——U4.5

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1523. 学生课程列表

题目

解析

答案

#include <iostream>
#include <string>
#include <unordered_map>
#include <vector>
#include <algorithm>
using namespace std;
unordered_map<string, vector<int>> students;
int n, k;
int main()
{
    cin >> n >> k;
    while (k --)
    {
        int class_id, students_num;
        cin >> class_id >> students_num;
        
        string name;
        for (int i = 0; i < students_num; i ++) 
        {
            cin >> name;
            students[name].push_back(class_id);
        }
    }
    while (n --)
    {
        string name;
        cin >> name;
        
        cout << name << ' ' << students[name].size();
        sort(students[name].begin(), students[name].end());
        for (int i = 0; i < students[name].size(); i ++) cout << ' ' << students[name][i];
        cout << endl;
        // 这四行的简单写法：
        // auto &all = students[name];
        // sort(all.begin(), all.end());
        // cout << name << ' ' << all.size();
        // for (auto a : all) cout << ' ' << a;
        // cout << endl;
        
    }
    return 0;
}