LeetCode.387.First Unique Character in a String

原題鏈接：First Unique Character in a String

題目內容：
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.

給出一個字符串，找到第一個沒有在字符串重複出現的字符，返回它的索引。如果找不到返回-1

---

Python

class Solution(object):
    def firstUniqChar(self, s):
        """
        :type s: str
        :rtype: int
        """
        if not s:
            return -1
        res = 0
        letters = [0 for i in range(0, 26)]
        for letter in s:
            letters[ord(letter)-97] = letters[ord(letter)-97] + 1 
        for i in s:
            if letters[ord(i)-97] == 1:
                return s.index(i)
        return -1

Tips：一定要細心，注意”cc”，”“這樣的字符串。邊界處理要做好！