PTA L2-042 老板的作息表 (25 分)

#include
#include
#include
using namespace std;
int main()
{int n;cin>>n;vector<pair<string,string>> s;for(int i=0;i<n;i++){string a,b,c;cin>>a>>c>>b; s.push_back({a,b});}sort(s.begin(),s.end());string la="-1";for(auto &p:s){if(la=="-1"){la=p.second;if(p.first!="00:00:00")cout<<"00:00:00 - "<<p.first<<endl;}else{if(la!=p.first) cout<<la<<" - "<<p.first<<endl;la=p.second;}}if(la!="23:59:59") cout<<la<<" - 23:59:59"<<endl;return 0;
}