But also must say that i'm thinking using negamax algorithm if i will not figure where i go wrong....

certainly negamax is a simpler and cleaner algorithm.  One thing to keep in mind is if you intend to reuse your algorithm for >2 player games or games with multisteps per play you won't be able to use negamax as there is an assumption built into the call that the next level down is your single opponent. if this is not the case then I would suggest moving to negamax will save you potential headaches later on

It's not obvious how to use minimax in games with more than 2 players anyway. I would look into Monte Carlo Tree Search if you want to write engines for a larger class of games.

Minimax doesn't work very well with more than 2 players anyway. I would look into Monte Carlo Tree Search if you want to write engines for a larger class of games.

But also must say that i'm thinking using negamax algorithm if i will not figure where i go wrong....

certainly negamax is a simpler and cleaner algorithm.  One thing to keep in mind is if you intend to reuse your algorithm for >2 player games or games with multisteps per play you won't be able to use negamax as there is an assumption built into the call that the next level down is your single opponent. if this is not the case then I would suggest moving to negamax will save you potential headaches later on

Minimax doesn't work very well with more than 2 players anyway. I would look into Monte Carlo Tree Search if you want to write engines for a larger class of games.