Learning-competitive-coding/First_Unique_Character_in_a_String.py at master · raniyer/Learning-competitive-coding · GitHub

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"""
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:
    def firstUniqChar(self, s: str) -> int:
        from collections import Counter
        s1 = Counter(s)
        for i in s1:
            if s1[i]==1:
                return s.index(i)
        return -1