leetcode 389. Find the Difference 牛人用异或 或者 求和 解决，很简单。

389. Find the Difference

 

Question Editorial Solution

  My Submissions

• Total Accepted: 7465
• Total Submissions: 14609
• Difficulty: Easy

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.

我的解法：利用hashmap进行记录

public class Solution {
public char findTheDifference(String s, String t){
    Map map=new HashMap();
    for(int i=0;i


牛人解法：

java 用异或：

public char findTheDifference_B(String s, String t) {
	char c = 0;
	for (int i = 0; i < s.length(); ++i) {
		c ^= s.charAt(i);
	}
	for (int i = 0; i < t.length(); ++i) {
		c ^= t.charAt(i);
	}
	return c;
}

或者用求和，c:

char findTheDifference(char* s, char* t) {
    int sum1=0,sum2=0;
    for(;*s;s++)
        sum1+=*s;
    for(;*t;t++)
        sum2+=*t;
    return sum2-sum1;
}