1047. Student List for Course (25)

考察倒排索引

注意如果用string的话会超时，因为string的copy时间以及比较时间都要比char数组的相应操作更耗时

#include<iostream>#include<vector>#include<string.h>#include<algorithm>typedef struct Student {char name[20];}Student;std::vector<Student> sVec;bool cmp(int s1, int s2){return strcmp(sVec[s1].name, sVec[s2].name) < 0;}int main(){int s, c;while(scanf("%d%d",&s,&c)!=EOF){std::vector<std::vector<int>> cVec(c);sVec.resize(s);//input for(int i = 0; i < s; ++i){int k;scanf("%s %d",sVec[i].name, &k);while(k--){int cid;scanf("%d",&cid);cVec[cid-1].push_back(i);}}//sort and outputfor(int i = 0; i < (int)cVec.size(); ++i){printf("%d %d\n",i+1, (int)cVec[i].size());std::sort(cVec[i].begin(), cVec[i].end(), cmp);for(int j = 0; j < (int)cVec[i].size(); ++j){printf("%s\n",sVec[cVec[i][j]].name);}}}return 0;}