2020-03-21(ccf201503-3节日）

纪念我的一次过的题目
　　　　　　　　　　　　　　　 啦啦啦啦啦啦啦啦

思路：先计算1850年1月1日到每年year年a月1日的天数days，int weekday = days%7+2就是a月1日为星期weekday。知道了要计算的月份第一天为星期几，再去计算第a个月的第b个星期c,

#include <iostream>
 using namespace std;
 
const int INF = 0x3f3f3f3f;
bool isRun(int x)
{
    if(x % 400 == 0) return true;
    if(x % 4 == 0 && x % 100 != 0) return true;
    return false; 
}

int rmonths[13] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int months[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int a, b, c, y1, y2;

int get_date(int year)
{
    long total_days = 0;
    int flag = true; // true 表示今年闰年 
    if(isRun(year))    for(int i = 1; i<=a-1; i++) total_days += rmonths[i];
    else 
    {
        for(int i = 1; i<=a-1; i++) total_days += months[i];
        flag = false;
    }
     
    
    for(int i = 1850; i < year; i++) 
    {
        if(isRun(i)) total_days += 366;
        else total_days += 365;
    }
    
    int week_day = total_days % 7 + 2; // week_day 表示当前月份的 1 号是星期几 
    if(week_day == 8) week_day = 1;
    if(week_day == 9) week_day = 2;
    
    int days = 0; 
//  if(c >= week_day) days += c - week_day;
//  else days += c + 7 - week_day;
    days += (c - week_day + 7) % 7;
    
    days = days + (b-1) * 7;
    if(flag) 
     {
        if(days + 1 > rmonths[a]) return INF;
     }
     else if(days + 1 > months[a]) return INF;
     
     return days;
    
}
 int main()
 {
     
     cin>>a>>b>>c>>y1>>y2;
     if(y1 > y2) swap(y1, y2);
     for(int i = y1; i<=y2; i++)
     {
        int date = get_date(i);
        if(date == INF) cout<<"none"<<endl;
        else
        {
            date += 1;
           printf("%d/%02d/%02d\n", i, a, date);
        }
    }
        
}