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.

解答

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public class Solution {
	public char findTheDifference(String s, String t) {
		int si = 0;
		int ti = 0;
		for (int i = 0; i < s.length(); i++) {
			si ^= (int) s.charAt(i);
		}
		for (int i = 0; i < t.length(); i++) {
			ti ^= (int) t.charAt(i);
		}
		return (char) (si ^ ti);
	}
}