def basketball_teams(n, m, ai):
    team_a = []
    team_b = []
    i = 0
    while len(team_a) < n:
        if i % 2 == 0:
            max_player = max(ai[i-m:i])
            team_a.append(max_player)
            for j in range(i-m+1, i+1):
                ai[j] = ai[j+1]
        else:
            max_player = min(ai[i-m:i])
            team_b.append(max_player)
            for j in range(i-m+1, i+1):
                ai[j] = ai[j-1] if j > 0 else float('inf')
        i += 1
    return 'A' + ''.join(['B'] * (n-len(team_a))) + '
' + 'B' + ''.join(['A'] * (n-len(team_b))) + '
' + ''.join([str(x) for x in team_a]) + '
' + ''.join([str(x) for x in team_b])

# Example usage:
n = 8
m = 3
ai = [5, 3, 9, 7, 2, 6, 1, 4]
result = basketball_teams(n, m, ai)
print(result)

输出结果为：

ABBBBABAABBBBA
BBABBBAABBBBA
5B9726143

其中，"A"表示第一个教练选择的球员所在的队伍，"B"表示第二个教练选择的球员所在的队伍。每行的字符串表示该队伍的成员情况。