02-leetcode: explore-strings-34 字符串中的第一个唯一字符

Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1.

Examples:

s = "leetcode"
return 0.

s = "loveleetcode",
return 2.
Note: You may assume the string contain only lowercase letters.

class Solution(object):
    def firstUniqChar(self, s):
        """
        :type s: str
        :rtype: int
        """
        if not s:
            return -1

        d = {}
        for i in range(len(s)):
            if d.get(s[i]):
                continue
            if s.count(s[i]) > 1:
                d[s[i]] = 1
                continue
            return i

        return -1