Leetcode刷题记录——面试题 01.01. 判定字符是否唯一

遍历字符串
使用字典记录所遇到的所有字符
若后续遇见的字符在字典中
break并返回False
否则返回True

class Solution:
    def isUnique(self, astr: str) -> bool:
        thisdict = {}
        for letter in astr:
            if letter not in thisdict:
                thisdict[letter] = 1
            else:
                return False
        return True