1047 Student List for Course

来源：互联网发布：带数据统计的二维码编辑：程序博客网时间：2024/06/06 13:58

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
解题思路：上一题是有信息输出学生的情况，这一题是由信息输出课程的情况，一开始用string来表示学生的姓名，结果最后一个case又超时了，然后我就试着把用string表示名字再变成用数字来表示名字，用名字转换为哈希表的下标来表示名字，过了。最后输出之前，数字的排序比string的排序快吧。
#include<iostream>#include<vector>#include<map>#include<stdio.h>#include<algorithm>#include<string>using namespace std;int main(){for (int student_num, course_num; scanf("%d%d", &student_num, &course_num) != EOF;){vector<vector<int>>stu_list(course_num+1);while (student_num--){char name[5];scanf("%s", name);int index = (name[0] - 'A') * 26 * 26 * 10 + (name[1] - 'A') * 26 * 10 + (name[2] - 'A') * 10 + (name[3] - '0');int register_num;scanf("%d", &register_num);int course_id;while (register_num--){scanf("%d", &course_id);stu_list[course_id].push_back(index);}}for (int i = 1; i < course_num + 1; i++){cout << i << " " << stu_list[i].size() << endl;sort(stu_list[i].begin(), stu_list[i].end());for (int j = 0; j < stu_list[i].size(); j++){printf("%c%c%c%c\n", stu_list[i][j] / (26 * 26 * 10) + 'A',(stu_list[i][j]%(26*26*10))/(26*10) + 'A',(stu_list[i][j]%(26*10))/10 +'A',(stu_list[i][j]%(10)) + '0');}}}return 0;}

0 0