题意：求某天是星期几。

题解：数学||模板

View Code 
 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 char name[][12] = { "monday", "tuesday", "wednesday",
 6                  "thursday", "friday", "saturday", "sunday"
 7                };
 8 int main(void)
 9 {
10     int d, m, y, a;
11     while(scanf("%d%d%d",&y,&m,&d)!=EOF)
12     {
13         if (m==1||m==2)
14         {
15             m+=12;
16             y--;
17         }
18         if((y<1752)||(y==1752&&m<9)||(y==1752&&m==9&&d<3))
19             a=(d+2*m+3*(m+1)/5+y+y/4+5)%7;
20         else
21             a=(d+2*m+3*(m+1)/5+y+y/4-y/100+y/400)%7;
22         puts(name[a]);
23     }
24     return 0;
25 }