袁老师学生版题解

#include<bits/stdc++.h>
using namespace std;

bool isLeapYear(int y)
{
	if(y%400==0)
		return 1;
	else if(y%100==0)
		return 0;
	else if(y%4==0)
		return 1;
	else
		return 0;
}

int main()
{
	int a,b,c;
	char tmp;
	cin >> a >> tmp >> b >> tmp >> c;

	int mdays[13] = {0,31,28+isLeapYear(a),31,30,31,30,31,31,30,31,30,31}; 
	
	if(a<1971 || a>2100)
		cout << "YES";
	else if(b<1 || b>12)
		cout << "YES";
	else if(c<1 || c> mdays[b])
		cout << "YES";
	else
		cout << "NO";
	return 0;
}