387. First Unique Character in a String

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.

Solution

(1) Java

(2) Python

class Solution:
    def firstUniqChar(self, s):
        """
        :type s: str
        :rtype: int
        """
        chars = [0]*26
        for c in s:
            chars[ord(c)-ord('a')] += 1
        for i, c in enumerate(s):
            if chars[ord(c)-ord('a')] == 1:
                return i
        return -1

(3) Scala