#include<iostream>
using namespace std;

int days[] = {0,31,28,31,30,31,30,31,31,30,31,30,31};

int is_leap(int y){   //判断闰年
	return y % 400 == 0 || y % 4 == 0 && y % 100 != 0;
}

int daysOfMonth(int y, int m){
	if( m == 2)
		return is_leap(y) + 28;
	return days[m];
}

int main(){
	int y = 2000, m = 1, d = 1, w = 6;   // 年，月，日，周几
	int ans = 0; 
	while(y != 2020 || m != 10 || d != 2){
		if(d == 1 || w == 1)
			ans += 2;
		else 
			ans++;
		d++;
		if(d > daysOfMonth(y, m))
			d = 1, m++;
		if(m > 12)
			m = 1, y++;
		w++;
		if(w == 8)
			w = 1;
	}
	cout << ans << endl;
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
int week=6,sum;
int main(){
	for(register int year=2000;year<=2020;year++){
		int	a[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
		if((year%4==0&&year%100!=0)||year%400==0)a[2]=29;//闰年特判
		for(register int month=1;month<=12;month++)
			for(register int day=1;day<=a[month];day++){
				if(day==1||week==1)sum+=2;//月初或者周一
				else sum++;
				week=(week+1)%7;//星期数增加
				if(year==2020 && month==10 && day==1){
					cout<<sum;
					return 0;
				}
			}
	}
}

闰年是能被400整除或者能整除4但不能整除100的年，闰年2月份是29天，非闰年是28天

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"
int yue[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
int main(){
	ll ans=0;
	int zhou=5;
	for(int i=2000;i<=2020;i++){
		if(i%400==0||(i%4==0&&i%100!=0)){
			yue[2]=29;
		}
		else yue[2]=28;
		for(int j=1;j<=12;j++){
			for(int k=1;k<=yue[j];k++){
				zhou++;
				zhou%=8;
				if(zhou==0) zhou=1;
				if(zhou==1||k==1) ans+=2;
				else ans++;
				if(i==2020&&j==10&&k==1){
					cout<<ans;
					return 0;
				}
			}
		}
	}
	return 0;
}