387. First Unique Character in a String

https://leetcode.com/problems/first-unique-character-in-a-string/#/description

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
        """
        count = {}
        for c in s:
            if c in count.keys():
                count[c] += 1
            else:
                count[c] = 1

        for i in range(len(s)):
            c = s[i]
            if count[c] == 1:
                return i
        return -1