#include <iostream> #include <vector> #include <map> using namespace std; int main(){ int n; cin >> n; map<string, vector<string> > m; string time, code; for(int i = 0;i < n;i++){ cin >> time >> code; if(m.find(time) == m.end()){ vector<string> v; v.push_back(code); m[time] = v; }else{ m[time].push_back(code); } } map<string, vector<string> >::iterator it = m.begin(); int flag = 1; for(;it != m.end();++it){ if(it->second.size() > 1){ flag = 0; cout << it->first; for(int i = 0;i < it->second.size();i++){ cout << " " << it->second[i]; } cout << endl; } } if(flag == 1){ cout << "YES" << endl; } return 0; } C++的，没记错的话应该是AC了，一开始忘了YES这一茬（我是被北方同学带偏了普通话的土生土长的广东人