package tictactoe

// Minimax is for retrieving the optimal value for maximizer.
//  depth is the current depth in the game tree
//  nodeIndex is the current index of node in scores
//  isMax is true if the current move is a maximizer
//  scores stores the Game Tree
//  height is the max height of the Game Tree
func Minimax(depth, nodeIndex int, isMax bool, scores []int, height int) int {
	// terminate if end of the tree reached
	if depth == height {
		return scores[nodeIndex]
	}
	if isMax {
		left := Minimax(depth+1, nodeIndex*2, false, scores, height)
		right := Minimax(depth+1, nodeIndex*2+1, false, scores, height)
		return max(left, right)
	}
	left := Minimax(depth+1, nodeIndex*2, true, scores, height)
	right := Minimax(depth+1, nodeIndex*2+1, true, scores, height)
	return min(left, right)
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}