minmax

import math

def minimax(tree, depth, isMax):

    # If we reach leaf level
    if depth == 1:
        if isMax:
            return max(tree)
        else:
            return min(tree)

    # Maximizing player
    if isMax:
        best = -math.inf
        for branch in tree:
            value = minimax(branch, depth-1, False)
            best = max(best, value)
        return best

    # Minimizing player
    else:
        best = math.inf
        for branch in tree:
            value = minimax(branch, depth-1, True)
            best = min(best, value)
        return best


# Tree from diagram
tree = [
    [3,5,2,9],
    [12,5,6],
    [23,25,1]
]

depth = 2

print("Optimal Value:", minimax(tree, depth, True))