CareerCup

def nearestDouble(str):
    if str[0] == str[1]:
        return str[0]
    num = int(str, 16)
    doubles = [0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff]
    min_diff = 16
    argmin = -1
    # We could reduce the number of comparisons here.
    # I'm searching for argument minimum in a dumb way to simplify the idea
    for i in doubles:
        diff = abs(i - num)
        if diff < min_diff:
            min_diff = diff
            argmin = i
    # We take last digit here because it would be something like 0x0d and I'm to lazy to read how to format hex
    return hex(argmin % 16)[-1] 


def shortenColor(rrggbb):
    # We are using here additivity of loss function: we can minimize each component of rgb independently
    r = nearestDouble(rrggbb[1:3])
    g = nearestDouble(rrggbb[3:5])
    b = nearestDouble(rrggbb[5:7])
    return "#{}{}{}".format(r, g, b)


assert shortenColor("#09f166") == "#1e6"

def shorten(color):
    color = int(color, 16)
    lower = (color / 0x11) * 0x11
    higher = ((color / 0x11) + 1) * 0x11

    if (color - lower) < (higher - color):
        return hex(lower)[3]
    else:
        return hex(higher)[3]

def nearest_short_color(long_color):
    red = shorten(long_color[1:3])
    green = shorten(long_color[3:5])
    blue = shorten(long_color[5:7])

    return '#{}{}{}'.format(red, green, blue)


if __name__ == '__main__':
    print nearest_short_color('#09f166')