随机打乱数组

    function randomSort(arr) {
        for (let i = arr.length - 1; i >= 0; i--) {
            randomIndex = Math.floor(Math.random() * (i + 1))
            let [x, y] = [arr[randomIndex], arr[i]]
            arr[randomIndex] = y;
            arr[i] = x;
        }
        return arr
    }