PAT 乙级1026 程序运行时间

#include <iostream>
#include <cstdio>

int main(){
    int start,end;
    scanf("%d%d",&start,&end);
    int t = end-start;
    int hours = t / 360000;
    t = t-(t / 360000)*360000;
    int minutes = t / 6000;
    t = t-(t / 6000)*6000;
    int seconds = t / 100;
    if (t % 100 > 49 )
        seconds++;
    printf("%.2d:%.2d:%.2d",hours,minutes,seconds);
}