超容易记的快排，改写自Acwing的cpp代码
```js
function sort(arr) {
quickSort(arr, 0, arr.length - 1);
console.log(arr);
}
function quickSort(arr, left, right) {
if (left >= right) return;
let x = arr[Math.floor((left + right) / 2)];
let i = left - 1, j = right + 1;
while (i < j) {
for (i ++; arr[i] < x; i ++ );
for (j --; arr[j] > x; j -- );
if (i < j) {
[arr[i], arr[j]] = [arr[j], arr[i]];
}
}
quickSort(arr, left, j);
quickSort(arr, j + 1, right);
}
```
