USACO 1.1 Friday the Thirteenth (friday)

/*
ID: haolink1
PROG: friday
LANG: C++
*/
//#include 
  
   
#include 
   
     #include 
    
      #include 
     
       using namespace std; int isleap(int year){ return year%4==0 && (year%100 != 0 || year%400 == 0); } /* return length of month m in year y */ int MonthLen(int year, int month,int* month_table){ if(month == 1) /* february */ return month_table[month]+isleap(year); else return month_table[month]; } int main(){ ifstream fin("friday.in"); string period_str; getline(fin,period_str); int period = atoi(period_str.c_str()); //start form Saturday int category_couter[] = {0,0,0,0,0,0,0}; int month_table[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; //January 13, 1900 was a Saturday,so day_of_week = 0 int day_of_week = 0; for(int current_year = 1900;current_year<1900+period;current_year++){ for(int month=0;month<12;month++){ category_couter[day_of_week]++; day_of_week=(day_of_week+MonthLen(current_year,month,month_table))%7; } } ofstream fout("friday.out"); int i=0; for(;i<6;i++){ fout<