#include <stdio.h>

__int64 a, b, c;
int n ;

main () 
{
    int i ;
    while (scanf ("%d" , &n) , n != -1){
        if (n % 2){printf ("0\n") ; continue ;} 
        if (!n){printf ("1\n") ; continue ;} 
        n /= 2 ;
        a = 3; b = 11 ;
        for (i = 3; i <= n; i ++ ){
            c = 4 * b - a ;
            a = b ;
            b = c ;}
        if (n == 1) printf ("3\n") ;
        else printf ("%I64d\n" , b) ;}
}

• 顶啊，楼上说的好啊，__int64 rp; while (1) rp++; (0) applepi 2010-10-23 22:55:02