//数组乱序    洗牌算法Fisher–Yates shuffleArray.prototype.shuffle = function() {    var input = this;    for (var i = input.length-1; i >=0; i--) {        var randomIndex = Math.floor(Math.random()*(i+1));        var itemAtIndex = input[randomIndex];        input[randomIndex] = input[i];        input[i] = itemAtIndex;    }    return input;}//数组排列组合Array.prototype.permute = function() {    var permArr = [],        usedChars = [];    var input = this;    function main(input){        var i, ch;        for (i = 0; i < input.length; i++) {            ch = input.splice(i, 1)[0];            usedChars.push(ch);            if (input.length == 0) {                permArr.push(usedChars.slice());            }            main(input);            input.splice(i, 0, ch);            usedChars.pop();        }        return permArr    }    return main(input);}