Check Distances Between Same Letters — Python

# Time:  O(n)
# Space: O(1)

# hash table
class Solution(object):
    def checkDistances(self, s, distance):
        """
        :type s: str
        :type distance: List[int]
        :rtype: bool
        """
        for i in xrange(len(s)):
            if i+distance[ord(s[i])-ord('a')]+1 >= len(s) or s[i+distance[ord(s[i])-ord('a')]+1] != s[i]:
                return False
            distance[ord(s[i])-ord('a')] = -1
        return True