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

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

    Output:
    idx -- list of indices of the local maxima in x
    """
    sol = []
    for idx, num in enumerate(x):
        if idx == 0 and num =>  x[idx+1]:
            sol.append(idx)
        elif idx == len(x)-1 and num => x[idx-1]:
            sol.append(idx)
        else:
            if x[idx-1] <= num and num => x[idx+1]:
                sol.append(idx)

    return  sol