leetcode 387. First Unique Character in a String

Python leetcode

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.

#coding=utf-8

#求一个字符串的第一个不重复的字符，返回它的下标

'''

Examples:

s = "leetcode"

return 0.

s = "loveleetcode",

return 2.

'''

import string

class Solution(object):

    def firstUniqChar(self, s):

        """

        :type s: str

        :rtype: int

        """

        #这个简单的方法  time limit

        '''

        for x in s:

            if s.count(x) == 1:

                return s.index(x)

        '''

        #方法2与3的核心在于找满足要求的最小位置加了个find()操作，这样就保证是最先出现的

        #方法2:

        #return min([s.find(x) for x in string.lowercase if s.count(x)==1] or [1])

        #方法3

        from collections import Counter

        return min([s.find(x) for x,v in Counter(s).iteritems() if v==1] or [-1])

s='leetcode'

S=Solution()

print S.firstUniqChar(s)