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最新推荐文章于 2023-02-11 21:49:20 发布

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本文探讨了在平年中，如何判断两个指定的相邻月份的第一天是否能分别对应一周中的两天。通过分析不同月份天数对一周周期的影响，得出结论并提供了具体的编程实现。

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题目链接：点击打开链接

You are given names of two days of the week.

Please, determine whether it is possible that during some non-leap year the first day of some month was equal to the first day of the week you are given, while the first day of the next month was equal to the second day of the week you are given. Both months should belong to one year.

In this problem, we consider the Gregorian calendar to be used. The number of months in this calendar is equal to 12. The number of days in months during any non-leap year is: 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31.

Names of the days of the week are given with lowercase English letters: "monday", "tuesday", "wednesday", "thursday", "friday", "saturday", "sunday".

Input

The input consists of two lines, each of them containing the name of exactly one day of the week. It's guaranteed that each string in the input is from the set "monday", "tuesday", "wednesday", "thursday", "friday", "saturday", "sunday".

Output

Print "YES" (without quotes) if such situation is possible during some non-leap year. Otherwise, print "NO" (without quotes).

   Examples
 
     input
   
monday
tuesday

     output
   
NO

     input
   
sunday
sunday

     output
   
YES

     input
   
saturday
tuesday

     output
   
YES

Note

In the second sample, one can consider February 1 and March 1 of year 2015. Both these days were Sundays.

In the third sample, one can consider July 1 and August 1 of year 2017. First of these two days is Saturday, while the second one is Tuesday.

大意：判断是否存在相邻月份的第一天满足给出的例子

题解：题目已经确定是平年，星期的周期是 7，而月份相差天数只有三种情况 28，30，31；其对应的周期余数为 0，2，3。

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
char a[10],b[10];
// 0 2 3
int main()
{
	while(~scanf("%s%s",a,b))
	{
		if(a[0]=='m')
		{
			if(b[0]=='m'||b[0]=='w'||(b[0]=='t'&&b[1]=='h'))
				puts("YES");
			else	puts("NO");
		}
		if(a[0]=='t'&&a[1]=='u')
		{
			if(b[0]=='t'||b[0]=='f')
				puts("YES");
			else	puts("NO");
		}
		if(a[0]=='w')
		{
			if(b[0]=='w'||b[0]=='f'||(b[0]=='s'&&b[1]=='a'))
				puts("YES");
			else	puts("NO");
		}
		if(a[0]=='t'&&a[1]=='h')
		{
			if((b[0]=='t'&&b[1]=='h')||b[0]=='s')
				puts("YES");
			else	puts("NO");
		}
		if(a[0]=='f')
		{
			if(b[0]=='f'||(b[0]=='s'&&b[1]=='u')||b[0]=='m')
				puts("YES");
			else	puts("NO");
		}
		if(a[0]=='s'&&a[1]=='a')
		{
			if((b[0]=='s'&&b[1]=='a')||b[0]=='m'||(b[0]=='t'&&b[1]=='u'))
				puts("YES");
			else	puts("NO");
		}
		if(a[0]=='s'&&a[1]=='u')
		{
			if((b[0]=='s'&&b[1]=='u')||(b[0]=='t'&&b[1]=='u')||b[0]=='w')
				puts("YES");
			else	puts("NO");
		}
	}
	return 0;
}