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.

Solution:

XOR all elements.

Pairs will cancel out.



Code:

public class Solution {
    public char findTheDifference(String s, String t) {
        char xor = 0;
        for (char c : s.toCharArray()) {
            xor ^= c;
        }
        for (char c : t.toCharArray()) {
            xor ^= c;
        }
        return xor;
    }
}