PAT

Zhejiang University has 40000 students and provides 2500 courses. Now given the registered course list of each student, you are supposed to output the student name lists of all the courses.

Input Specification:

Each input file contains one test case. For each case, the first line contains 2 numbers: N (<=40000), the total number of students, and K (<=2500), the total number of courses. Then N lines follow, each contains a student's name (3 capital English letters plus a one-digit number), a positive number C (<=20) which is the number of courses that this student has registered, and then followed by C course numbers. For the sake of simplicity, the courses are numbered from 1 to K.

Output Specification:

For each test case, print the student name lists of all the courses in increasing order of the course numbers. For each course, first print in one line the course number and the number of registered students, separated by a space. Then output the students' names in alphabetical order. Each name occupies a line.

Sample Input:

10 5ZOE1 2 4 5ANN0 3 5 2 1BOB5 5 3 4 2 1 5JOE4 1 2JAY9 4 1 2 5 4FRA8 3 4 2 5DON2 2 4 5AMY7 1 5KAT3 3 5 4 2LOR6 4 2 4 1 5

Sample Output:

1 4ANN0BOB5JAY9LOR62 7ANN0BOB5FRA8JAY9JOE4KAT3LOR63 1BOB54 7BOB5DON2FRA8JAY9KAT3LOR6ZOE15 9AMY7ANN0BOB5DON2FRA8JAY9KAT3LOR6ZOE1

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给定条件：
1.n个学生，k个课程
2.每个学生的参与课程信息

要求：
1.分别输出每门课的学生名单

解答：
1.用vector数组分别存储每门课的学生
2.排序后输出即可

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#include <cstdio>#include <cstring>#include <vector>#include <algorithm>using namespace std;int n, k, id;vector<int> v[2510];char name[40005][5];bool cmp(int i, int j) {return strcmp(name[i], name[j]) < 0;}int main() {freopen("input.txt", "r", stdin);scanf("%d%d", &n, &k);for(int i = 1; i <= n; i++) {scanf("%s",name[i]);int cnt;scanf("%d",&cnt);for(int j = 0; j < cnt; j++) {scanf("%d", &id);v[id].push_back(i);}}for(int i = 1; i <= k; i++) {printf("%d %d\n", i, (int)v[i].size());sort(v[i].begin(), v[i].end(), cmp);for(int j = 0; j < v[i].size(); j++) {printf("%s\n", name[v[i][j]]);}}return 0;}