LeetCode 953 Verifying an Alien Dictionary

class Solution(object):
    def isAlienSorted(self, words, order):
        """
        :type words: List[str]
        :type order: str
        :rtype: bool
        """
        order_map = {}
        for i, v in enumerate(order):
            order_map[v] = i

        def cmp_alien(x, y):
            ls = min(len(x), len(y))
            index = 0
            while index < ls:
                if x[index] != y[index]:
                    return order_map[x[index]] - order_map[y[index]]
                index += 1
            return len(x) - len(y)
        pos = 0
        while pos + 1 < len(words):
            if cmp_alien(words[pos], words[pos + 1]) > 0:
                return False
            pos += 1
        return True


if __name__ == '__main__':
    s = Solution()
    print s.isAlienSorted(["hello","leetcode"], "hlabcdefgijkmnopqrstuvwxyz")
    print s.isAlienSorted(["word","world","row"], "worldabcefghijkmnpqstuvxyz")
    print s.isAlienSorted(["apple","app"], "abcdefghijklmnopqrstuvwxyz")