FOJ 1164 Average is not Fast Enough!

#include<stdio.h>#include<string.h>#include<iostream>using namespace std;int main(){   //freopen("1.txt","r",stdin);

    int n,m,i,hour,min,second;    double d;    scanf("%d%lf",&n,&d);    while(scanf("%d",&m)!=EOF)    {        char str[30];        double sum=0;        bool mark=true;        for(i=0;i<n;i++)        {            scanf("%s",str);            if(strcmp(str,"-:--:--")==0) {mark=false;continue;}            sscanf(str,"%d:%d:%d",&hour,&min,&second);            sum+=hour*3600+min*60+second;        }        if(mark==false) {printf("%3d: -\n",m);continue;}        sum=sum/d+0.5;        printf("%3d: %d:%02d min/km\n",m,(int)sum/60,(int)sum%60);    }}