1006. Sign In and Sign Out

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

 struct stu
 {
     char ID[];
     int GetTime[];
     int LeaveTime[];
 };

 stu Student[];

 int main()
 {
     int n,i,j;
        int m;
     while(scanf("%d",&m)!=EOF)
     {

             for(j=;j<m;j++)
             {
                 scanf("%s %d:%d:%d %d:%d:%d",Student[j].ID,&Student[j].GetTime[],&Student[j].GetTime[],&Student[j].GetTime[],&Student[j].LeaveTime[],&Student[j].LeaveTime[],&Student[j].LeaveTime[]);
             }

             int GetHour,GetMin,GetSec,LeaveHour,LeaveMin,LeaveSec;

             GetHour=GetMin=GetSec=;
             LeaveHour=LeaveHour=LeaveSec=-;

             int OpenMan,CloseMan;

             for(j=;j<m;j++)
             {
                 if(Student[j].GetTime[]<GetHour)
                 {
                     GetHour=Student[j].GetTime[];
                     OpenMan=j;
                 }
                 else if(Student[j].GetTime[]==GetHour)
                 {
                     if(Student[j].GetTime[]<GetMin)
                     {
                         GetMin=Student[j].GetTime[];
                         OpenMan=j;
                     }
                     else if(Student[j].GetTime[]==GetMin)
                     {
                         if(Student[j].GetTime[]<GetSec)
                         {
                             GetSec=Student[j].GetTime[];
                             OpenMan=j;
                         }
                     }
                 }

                 if(Student[j].LeaveTime[]>LeaveHour)
                 {
                     LeaveHour=Student[j].LeaveTime[];
                     CloseMan=j;
                 }
                 else if(Student[j].LeaveTime[]==LeaveHour)
                 {
                     if(Student[j].LeaveTime[]>LeaveMin)
                     {
                         LeaveMin=Student[j].LeaveTime[];
                         CloseMan=j;
                     }
                     else if(Student[j].LeaveTime[]==LeaveMin)
                     {
                         if(Student[j].LeaveTime[]>LeaveSec)
                         {
                             LeaveSec=Student[j].LeaveTime[];
                             CloseMan=j;
                         }
                     }
                 }
             }

             printf("%s %s\n",Student[OpenMan].ID,Student[CloseMan].ID);

     }
     return ;
 }