389. Find the Difference

Given two strings s and t which consist of only lowercase letters.

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

Find the letter that was added in t.

Example:

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

Output: e

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

思路：遍历t的字符，看count(i)在t和s中是否相等，相等pass，不相等返回i

代码：python3

class Solution:
    def findTheDifference(self, s: str, t: str) -> str:
        arr=[]
        for i in t:
            if i in arr:
                pass
            else:
                if t.count(i)==s.count(i):
                    pass
                else:
                    return i