问题 B: Student List for Course (25)

问题 B: Student List for Course (25)

时间限制: 1 Sec  内存限制: 64 MB
提交: 239  解决: 144
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题目描述

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.

输入

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.

输出

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.

样例输入

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

样例输出

1 4
ANN0
BOB5
JAY9
LOR6
2 7
ANN0
BOB5
FRA8
JAY9
JOE4
KAT3
LOR6
3 1
BOB5
4 7
BOB5
DON2
FRA8
JAY9
KAT3
LOR6
ZOE1
5 9
AMY7
ANN0
BOB5
DON2
FRA8
JAY9
KAT3
LOR6
ZOE1

 

这一题和上一题正好相反，需要输出的是每个课程下的学生信息。

所以我们可以让vector表示课程代码，将学生信息存在每一个课程的vector中。

而学生的名字，我们可以用二维数组来存储，因为每个学生不重名，且只输入一次，所以每一个整型数字对应一个名字，这样我们存在vector中的就可以是名字对应的整形数字而不是字符串了。

最后要按字母顺序输出的时候，利用sort函数，而cmp函数就是比较对应的vector中存储的任意两个整数对应的字符串的大小strcmp(stu[a],stu[b]) <0

 

#include
#include 
#include 
#include 
using namespace std;

vector hashTable[2510];  //存储课程代码 
char stu[40010][5];           //存储学生名字 
bool cmp(int a,int b){        //先输出字符串字母序小的那一个 
	return strcmp(stu[a],stu[b])<0;
}

int main(){
	int n,k,i,count;
	char name[5];
	vector::iterator it;
	scanf("%d%d",&n,&k);
	getchar();
	for(int j=0;j