poj 2409 polya定理

polya定理的入门题

 1 #include <iostream>

 2 #include <cstring>

 3 #include <cstdio>

 4 using namespace std;

 5 

 6 int pow( int a, int n )

 7 {

 8   int r = 1;

 9   while ( n-- )

10   {

11     r = r * a;

12   }

13   return r;

14 }

15 

16 int gcd( int a, int b )

17 {

18   if ( b )

19   {

20     return gcd( b, a % b );

21   }

22   return a;

23 }

24 

25 int main ()

26 {

27   int c, s;

28   while ( scanf("%d%d", &c, &s), c + s )

29   {

30     int sum = 0;

31     for ( int i = 1; i <= s; i++ )

32     {

33       int tmp = gcd( i, s );

34       sum += pow( c, tmp );

35     }

36     if ( s & 1 )

37     {

38       sum += s * pow( c, ( s + 1 ) / 2 );

39     }

40     else

41     {

42       sum += ( s / 2 ) * ( pow( c, ( s / 2 ) + 1 ) + pow( c, ( s / 2 ) ) );

43     }

44     sum /= s * 2;

45     printf("%d\n", sum);

46   }

47     return 0;

48 }