LeetCode-387(字符串中的第一个唯一字符)

v1

• 遍历n， 字典记录出现字符出现的次数和第一次出现的索引
  时间O(n) + O(len(ret)) 空间O(n)

class Solution:
    def firstUniqChar(self, s: str) -> int:
        if s == "":
            return -1
        
        dic = {}
        sorts = []
        
        for idx, i in enumerate(s):
            if i not in sorts:
                sorts.append(i)
            if dic.get(i):
                dic[i][1] += 1
            else:
                dic[i] = [idx, 1]

        for i in sorts:
            if dic[i][1] == 1:
                return dic[i][0]

        return -1