[387. First Unique Character in a String] #leetcode

387_1014.py

# use dictionary
import collections

class Solution(object):
  # O(n)
    def firstUniqChar(self, s):
        """
        :type s: str
        :rtype: int
        """
        counts = collections.Counter(s)    
        for i, c in enumerate(s):
            if counts[c] == 1:
                return i 
        return -1
      
# use string count      
    def firstUniqChar(self, s):
        """
        :type s: str
        :rtype: int
        """
        
        letters='abcdefghijklmnopqrstuvwxyz'
        index=[s.index(l) for l in letters if s.count(l) == 1]
        return min(index) if len(index) > 0 else -1