找不同

[pwstrick]

389. 找不同

/**
 * @param {string} s
 * @param {string} t
 * @return {character}
 */
var findTheDifference = function(s, t) {
    const len1 = s.length,
        len2 = t.length;
    let one = 0;
    for(let i=0; i<len1; i++) {
        one ^= (s[i].charCodeAt() ^ t[i].charCodeAt())
    }
    one ^= t[len2 - 1].charCodeAt();
    return String.fromCharCode(one);
};