I had WA 26 too. Stuped mistake. =)

Was:
                (  v + f + i*p + k*q )%2==0 &&
                ( -v + f + i*p - k*q )%2==0 &&
                (  u + s - i*q - k*p )%2==0 &&
                ( -u + s - i*q + k*p )%2==0

This get AC:
                (  v + f + i*(p/g) + k*(q/g) )%2==0 &&
                ( -v + f + i*(p/g) - k*(q/g) )%2==0 &&
                (  u + s - i*(q/g) - k*(p/g) )%2==0 &&
                ( -u + s - i*(q/g) + k*(p/g) )%2==0