Solution 1 - XOR Cancellation

XOR every character code; paired characters cancel and leave the added character.

TimeComplexity: O(n)

SpaceComplexity: O(1)

""" 0389.1 - Find the Difference - Solution 1 - XOR Cancellation """

class Solution:
    def findTheDifference(self, s: str, t: str) -> str:
        x = 0
        for c in s + t:
            x ^= ord(c)
        return chr(x)

if __name__ == "__main__":
    print(Solution().findTheDifference("abcd", "abcde"))  # e

package main

import "fmt"

func findTheDifference(s, t string) byte {
	var x byte = 0
	for i := 0; i < len(s); i++ {
		x ^= s[i]
	}
	for i := 0; i < len(t); i++ {
		x ^= t[i]
	}
	return x
}

func main() {
	fmt.Printf("%c\n", findTheDifference("abcd", "abcde"))
}

0389 - Find the Difference

Solution 1 - XOR Cancellation