LeetCode 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:eExplanation:'e' is the letter that was added.

方法一：Runtime: 6 ms

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

方法二：Runtime: 6 ms

public char findTheDifference(String s, String t) {char[] count = new char[26];for (char c : s.toCharArray()) count[c - 97]++;for (char c : t.toCharArray()) if (count[c - 97]-- < 1) return c;return 'a';}