LeetCode - 389. Find the Difference

389. Find the Difference

class Solution(object):
    def findTheDifference(self, s, t):
        """
        :type s: str
        :type t: str
        :rtype: str
        """
        dic = {}
        for x in s:
            dic[x]  = dic.get(x, 0)+1;
        for x in t:
            if dic.get(x, 0)==0:
                return x
            else:
                dic[x] -= 1
        

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

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