zoj2771 Get Out of the Glass(DP)

#include <stdio.h>
#include <string.h>

long long F[ 61 ][ 4 ];

int main()
{
int i,j,k,n;
memset( F, 0L, sizeof( F ) );
F[ 0 ][ 0 ] = 1L;

for ( i = 1 ; i <= 60 ; ++ i )
for ( j = 0 ; j <= 3  ; ++ j )
if ( i%2 ) {
for ( k =  0  ; k < j ; ++ k )
F[ i ][ j ] += F[ i-1 ][ k ];
}else {
for ( k = j+1 ; k <= 3 ; ++ k )
F[ i ][ j ] += F[ i-1 ][ k ];
}
while ( scanf("%d",&n) != EOF ) {
long long sum = 0;
for ( i = 0 ; i < 3 ; ++ i )
sum += F[ n ][ i+n%2 ];
printf("%lld\n",sum);
}
return 0;
}