PAT 1006. Sign In and Sign Out

#include<iostream>#include<string>using namespace std;int main(){  int cnt;cin>>cnt;  string first,last,in("44:44:44"),out("00:00:00");  while(cnt--){    string a,b,c;cin>>a>>b>>c;    if(b<in){first=a;in=b;};    if(c>out){last=a;out=c;}  }  cout<<first<<' '<<last;  return 0;}