bisect for ascending and descending series

bisect_unidirectional.py

def bisect_asc(arr):
    if len(arr):
        return arr[-1] < arr[0]
    return True

def bisect_cmp(arr):
    if bisect_asc(arr):
        return lambda x, y: x > y
    return lambda x, y: x < y

def bisect_right(arr, val):
    l = -1
    r = len(arr)
    cmp = bisect_cmp(arr)
    while r - l > 1:
        e = (l + r) >> 1
        if cmp(arr[e], val):
            l = e
        else:
            r = e
    return r

def bisect_left(arr, val):
    l = -1
    r = len(arr)
    cmp = bisect_cmp(arr)
    while r - l > 1:
        e = (l + r) >> 1
        if cmp(arr[e], val):
            l = e
        else:
            r = e
    return l

def slice(arr, minimum, maximum):
    """Slice ascending or descending range."""
    a = max(0, bisect_left(arr, minimum))
    b = max(0, bisect_right(arr, maximum))
    if b - a > 1:
        return arr[a:b+1]
    if len(arr) <= 1:
        return arr[a:b]
    return []