There are at least two questions in your question:

What are some of the methods used to program the successful go playing program?

and

Are those methods considered to be artificial intelligence?

The first question is deep and technical, the second broad and philosophical.

The methods have been described in: Mastering the Game of Go with Deep Neural Networks and Tree Search.

The problem of Go or perfect information games in general is that:

exhaustive search is infeasible.

So the methods will concentrate on shrinking the search space in an efficient way.

Methods and structures described in the paper include:

• learning from expert human players in a supervised fashion
• learning by playing against itself (reinforcement learning)
• Monte-Carlo tree search (MCTS) combined with policy and value networks

The second question has no definite answer, as you will have at least two angles on AI: strong and weak.

All real-world systems labeled "artificial intelligence" of any sort are weak AI at most.

So yes, it is artificial intelligence, but it is non-sentient.

There are at least two questions in your question:

What are some of the methods used to program the successful go playing program?

and

Are those methods considered to be artificial intelligence?

The first question is deep and technical, the second broad and philosophical.

The methods have been described in: Mastering the Game of Go with Deep Neural Networks and Tree Search.

The problem of Go or perfect information games in general is that:

exhaustive search is infeasible.

So the methods will concentrate on shrinking the search space in an efficient way.

Methods and structures described in the paper include:

• learning from expert human players in a supervised fashion
• learning by playing against itself (reinforcement learning)
• Monte-Carlo tree search (MCTS) combined with policy and value networks

The second question has no definite answer, as you will have at least two angles on AI: strong and weak.

All real-world systems labeled "artificial intelligence" of any sort are weak AI at most.

So, yes, it is artificial intelligence, but it is non-sentient.