hdu 1452 Happy 2004 (快速幂+取模乘法逆元）

 1 #include<cstdio>
 2 #include<cstring>
 3 using namespace std;
 4 int f1(int x,int y)
 5 {
 6     int ans=1;
 7     while (y)
 8     {
 9         if (y&1) ans=ans*x%29;
10         x=x*x%29;
11         y>>=1;
12     }
13     return ans;
14 }
15 int f2(int x)
16 {
17     int i=1;
18     while (i)
19     {
20         if ((29*i+1)%x==0) break;
21         i++;
22     }
23     return (29*i+1)/x;
24 }
25 int main()
26 {
27     int x,a,b,c;
28     while (~scanf("%d",&x))
29     {
30         if (!x) break;
31         a=(f1(2,2*x+1)-1)%29;
32         c=(((f1(3,x+1)-1)%29)*f2(2))%29;
33         b=(((f1(22,x+1)-1)%29)*f2(21))%29;
34         printf("%d\n",(a*b*c)%29);
35     }
36     return 0;
37 }