C. Поиск максимумов

import numpy as np

def get_extremum_indices(
    ordinates: np.ndarray,
) -> tuple[np.ndarray, np.ndarray]:
    dif_sign = np.sign(np.array(ordinates[1:] - ordinates[:-1]))
    dif_dif = dif_sign[1:] - dif_sign[:-1]
    mask_max = dif_dif == -2
    mask_min = dif_dif == 2
    indices = np.arange(2, ordinates.shape[0]) - 1 #так как -2 и 2 указывают на предыдущий элемент
    max_indices = indices[mask_max]
    min_indices = indices[mask_min]
    return min_indices, max_indices

a = np.array([7, 8, 6, 2, 4, 7, 0, 2, 8, 7, 7, 0, 9, 9, 7])
res = get_extremum_indices(a)
print(res)