1047. Student List for Course (25)

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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
分析：
（1）用string和MAP来做，会比较清晰，但是用string会超过时间。
（2）所以要用C字符串来处理，同时结合了快排。
（3）在这个程序的基础上，尝试考虑用map会更清晰，但不知道会不会超时，有空试试。和39算是一个类型的。因此回去把39AC来复习这个方法。
#include <cstdio>#include <vector>#include <algorithm>#include <cstring>using namespace std;struct St{char name[10];};vector<St> sVec;bool cmp (int p,int q){return strcmp(sVec[p].name,sVec[q].name)<0;}int main (){int n,k;scanf ("%d%d",&n,&k);vector<vector<int>> cVec(k);sVec.resize(n);int i,j;for (i=0;i<n;i++){int t;scanf("%s %d",&sVec[i].name,&t);for (j=0;j<t;j++){int tmp;scanf("%d",&tmp);cVec[tmp-1].push_back(i);}}for (i=0;i<cVec.size();i++){printf("%d %d\n",i+1,cVec[i].size());sort(cVec[i].begin(),cVec[i].end(),cmp);for (j=0;j<cVec[i].size();j++){printf("%s\n",sVec[cVec[i][j]].name);}}//printf("1");return 0;}

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