如何编码人工神经网络（Tic-tac-toe）？

I want to play Tic-tac-toe using an artificial neural network. My configuration for the network is as follows: For each of the 9 fields, I use 2 input neuron. So I have 18 input neurons, of course. For every field, I have 1 input neuron for a piece of Player 1 and 1 neuron for a piece of Player 2. In addition to that, I have 1 output neuron which gives an evaluation of the current board position. The higher the output value is, the better is the position for Player 1. The lower it is, the better is it for Player 2.I want to play Tic-tac-toe using an artificial