SRM145 DIV2 250

一般编程题，但是题目的叙述方式真的好奇怪

class ImageDithering:
    def count(self, dithered, screen):
        counter = 0
        for line in screen:
            for ch in line:
                if ch in dithered:
                    counter += 1
        return counter


# test
o = ImageDithering()

# test case
assert(o.count('BW', ("AAAAAAAA",
 "ABWBWBWA",
 "AWBWBWBA",
 "ABWBWBWA",
 "AWBWBWBA",
 "AAAAAAAA")) == 24)