from typing import List


def are_qbits_adjacent(qbit_indices: List[int]) -> bool:
    """
    Checks if qbit indices are adjacent.
    :param qbit_indices: list of qbit indices.
    :return: true if adjacent, false otherwise.
    """
    if len(qbit_indices) == 1:
        # Trivially true
        return True

    if len(qbit_indices) > 2:
        for i in range(len(qbit_indices[:-1])):
            if qbit_indices[i] != qbit_indices[i + 1] - 1:
                return False
        return True

    return qbit_indices[0] == qbit_indices[1] - 1 or qbit_indices[1] == qbit_indices[0] - 1