Find the Difference

Question

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.

Tags

• String

Thought

Utilize the ASCII for finding the extra character.

Code

class Solution(object):
    def findTheDifference(self, s, t):
        """
        :type s: str
        :type t: str
        :rtype: str
        """
        result = 0
        for i, ch in enumerate(s):
            result += ord(t[i])
            result -= ord(ch)
        result += ord(t[-1])
        return chr(result)