389. Find the Difference

题目

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.

题目大意

给定两个字符串 s 和 t，它们只包含小写字母。字符串 t 由字符串 s 随机重排，然后在随机位置添加一个字母。请找出在 t 中被添加的字母。

解题思路

• 题目要求找出 t 字符串中比 s 字符串多出的一个字符。思路还是利用异或的性质，X^X = 0，将 s 和 t 依次异或，最终多出来的字符就是最后异或的结果。

代码

package leetcode

func findTheDifference(s string, t string) byte {
	n, ch := len(t), t[len(t)-1]
	for i := 0; i < n-1; i++ {
		ch ^= s[i]
		ch ^= t[i]
	}
	return ch
}

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