0387.first-unique-character-in-a-string

387. First Unique Character in a String

题目

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.

解题思路

见程序注释