#387 First Unique Character in a String

class Solution:
    def firstUniqChar(self, s: str) -> int:
        dic = {}
        out = []
        for e in s:
            dic[e] = dic.get(e, 0) + 1
        for item in dic:
            for i in range (len(s)):
                if dic[item] == 1 and s[i] == item:
                    out.append(i)
        out.sort()
        if not out:
            return -1
        return (out[0])
        
slight improvements

class Solution:
    def firstUniqChar(self, s: str) -> int:
        dic = {}
        out = []
        for e in s:
            dic[e] = dic.get(e, 0) + 1
        for item in dic:
            if dic[item] == 1:
                out.append(s.index(item))
        if not out:
            return -1
        return (min(out))

close to optimal (99% beating cocde) 
class Solution:
    def firstUniqChar(self, s: str) -> 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