HDU 2133 What day is it

What day is it

Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)

Total Submission(s): 2274 Accepted Submission(s): 667



[align=left]Problem Description[/align]
Today is Saturday, 17th Nov,2007. Now, if i tell you a date, can you tell me what day it is ?

[align=left]Input[/align]
There are multiply cases.

One line is one case.

There are three integers, year(0<year<10000), month(0<=month<13), day(0<=day<32).

[align=left]Output[/align]
Output one line.

if the date is illegal, you should output "illegal". Or, you should output what day it is.

[align=left]Sample Input[/align]

2007 11 17

[align=left]Sample Output[/align]

Saturday

思路：0年1月1日是星期六。每个日期都跟它比。

AC代码：

#include<iostream>
#include<string.h>
#define lev(n) (n%400==0||(n%4==0&&n%100!=0))
using namespace std;
int an[2][13]={{0,31,28,31,30,31,30,31,31,30,31,30,31},
{0,31,29,31,30,31,30,31,31,30,31,30,31}};
int illegal(int y,int m,int d)
{
if(m*d==0)return 1;
if(d>an[lev(y)][m]) return 1;
return 0;
}
int thisyear(int y,int m,int d)
{
int i,s=0;
for(i=0;i<m;i++)
s+=an[lev(y)][i];
return (s+d)%7;
}
int calc (int y,int m,int d)
{
int i,s=0;
for(i=0;i<y;i++)
s+=lev(i)?366:365;
return (s+thisyear(y,m,d)+4)%7;
}
int main()
{
int y,m,d;
char c[7][10]={"Monday","Tuesday","Wednesday",
"Thursday","Friday","Saturday","Sunday"};
while(scanf("%d%d%d",&y,&m,&d)!=EOF)
{
if(illegal(y,m,d)) puts("illegal");
else puts(c[calc(y,m,d)]);
}
return 0;
}