2024-02-05 07:12:58 +0000 UTC

class Solution:
    def firstUniqChar(self, s: str) -> int:
        counter = [0] * 26

        for char in s:
            idx = ord(char) - ord('a')
            if counter[idx] in (0, 1):
                counter[idx] += 1
        for i in range(len(s)):
            if counter[ord(s[i]) - ord('a')] == 1:
                return i
        return -1