def find_maxima(input_list):
    """Find local maxima of x.

    Input arguments:
    x -- 1D list of real numbers

    Output:
    idx -- list of indices of the local maxima in x
    """
    local_maxima = []
    for i, val in enumerate(input_list):
        if i == 0 or i == len(input_list)-1:
            continue
        if input_list[i-1] < val and input_list[i+1] < val:
            local_maxima.append(i)
    if len(input_list) > 0:
        if input_list[0] > input_list[1]:
            local_maxima.append(0)
        if input_list[-1] > input_list[-2]:
            local_maxima.append(len(input_list)-1)
    return sorted(local_maxima)