387. First Unique Character in a String

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
        """
        l=[0]*26
        for i in s:
            l[ord(i)-97]+=1
        for index,i in enumerate(s):
            if l[ord(i)-97]==1:
                return index
        return  -1