[leetcode]find the difference

题目描述

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:

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Input:
s = "abcd"
t = "abcde"

Output:
e

Explanation:
'e' is the letter that was added.

解题思路与代码

这个题类似Single Number，也就是两个字符串除了一个字符以外，其他字符都是两两相等，找出只出现一次的字符。代码如下：

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public class  {
    public char findTheDifference(String s, String t) {
        char ch = 0;

        for(int i = 0; i < s.length(); i++){
            ch ^= s.charAt(i);
            ch ^= t.charAt(i);
        }

        ch ^= t.charAt(t.length() - 1);

        return ch;
    }
}