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LeetCode 387 First Unique Character In A String - Easy

387. First Unique Character in a String

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387. First Unique Character In A String — Easy

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Problem

  1. First Unique Character in a String

Given a string, find the first non-repeating character in it and return its index. If it doesn't exist, return -1.

Examples:

s = "leetcode" return 0.

s = "loveleetcode" return 2.

Solution

class Solution:
    def firstUniqChar(self, s: str) -> int:
        counter = {}
        for char in s:
            counter[char] = counter.get(char, 0) + 1
        
        for i, char in enumerate(s):
            if counter[char] == 1:
                return i
        
        return -1

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