389. Find the Difference

C++

class Solution {
public:
    char findTheDifference(string s, string t) {
        int n = t.length();
        char c = t[n-1];
        for (int i = 0; i < n - 1; ++i) 
        {
            c ^= s[i];
            c ^= t[i];
        }
        return c;
    }
};

Java

public class Solution {
    public char findTheDifference(String s, String t) {
        int n = t.length();
        char c = t.charAt(n - 1);
        for (int i = 0; i < n - 1; ++i) 
        {
            c ^= s.charAt(i);
            c ^= t.charAt(i);
        }
        return c;
    }
}

Javascript

/**
 * @param {string} s
 * @param {string} t
 * @return {character}
 */
var findTheDifference = function(s, t) {
    var c = t.charCodeAt(t.length-1);           
    for(var i=0; i < s.length; i++){
        c = c ^ s.charCodeAt(i) ^ t.charCodeAt(i);
    }
    return String.fromCharCode(c);
    
};

我和答案思路一样，都是位运算

但是Javascript中还要进行unicode转换，不了解，做不出

JS的 “a”.charCodeAt(0)=97,作为数字就方便位运算了