原题

给出两个字符串，只有一处不同，一个字符串比两一个多一个字符，找出这个字符

样例

Input:
s = "abcd"
t = "abcde"

Output:
e

Explanation:
'e' is the letter that was added.

解题思路

• 合并两个字符串，题目转化为寻找单身狗

完整代码

class Solution(object):
    def findTheDifference(self, s, t):
        """
        :type s: str
        :type t: str
        :rtype: str
        """
        temp = 0
        for char in s + t:
            temp = temp ^ ord(char)
        return chr(temp)