First unique character in a string

class Solution:
    def firstUniqChar(self, s: str) -> int:
        count = Counter(s)
        for i in range(len(s)):
            if count[s[i]] == 1:
                return i
        return -1

First Unique Character in a String

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Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1.

 

Example 1:

Input: s = "leetcode"
Output: 0

Example 2:

Input: s = "loveleetcode"
Output: 2

Example 3:

Input: s = "aabb"
Output: -1

 

Constraints:

• 1 <= s.length <= 105
• s consists of only lowercase English letters.