動機

只有一個不一樣的就xor下去

Problem

You are given two strings s and t.

String t is generated by random shuffling string s and then add one more letter at a random position.

Return the letter that was added to t.

 

Example 1:

Input: s = "abcd", t = "abcde"Output: "e"Explanation: 'e' is the letter that was added.

Example 2:

Input: s = "", t = "y"Output: "y"

Example 3:

Input: s = "a", t = "aa"Output: "a"

Example 4:

Input: s = "ae", t = "aea"Output: "a"

 

Constraints:

    t
  • 0 <= s.length <= 1000
    • t
  • t.length == s.length + 1
    • t
  • s and t consist of lower-case English letters.

Sol

class Solution:
    def findTheDifference(self, s: str, t: str) -> str:
        a = reduce(lambda acc,x: acc^ord(x), s, 0)
        b = reduce(lambda acc,x: acc^ord(x), t, 0)
        return chr(a^b)