1047 Student List for Course

#include<iostream>
#include<vector>
#include<algorithm>
#include<string.h>
using namespace std;

struct student{
    char name[5];
    vector<int>course;
};

student s[40000];
vector<int>v[2501];

bool comp(student&x,student&y)
{
    return strcmp(x.name,y.name)<0;
}

int main()
{
    int N,K;//N人数，k课程
    int i,j,k;
    scanf("%d %d",&N,&K);
    getchar();
    
    for(i=0;i<N;i++){
        for(j=0;j<4;j++){
            s[i].name[j]=getchar();
        }
        getchar();
        s[i].name[j]=0;
        
        
        scanf("%d",&j);
        while(j--){
            scanf("%d",&k);
            s[i].course.emplace_back(k);
        }
        getchar();
    }
    
    sort(s,s+N,comp);
    
    for(i=0;i<N;i++){
        for(int each:s[i].course){
            v[each].emplace_back(i);
        }
    }
    
    
    
    for(i=1;i<=K;i++){
        printf("%d %zu\n",i,v[i].size());
        for(int each:v[i]){
            printf("%s\n",s[each].name);
        }
    }
}