QuickSort (快速排序法)

let arr = [14, -4, 17, 6, 8, -9];

quickSort(0, arr.length - 1);
console.log(arr);

function partition(start, r) {
  let x = arr[r]; // x 是 pivot
  let i = start - 1;
  for (let j = start; j <= r - 1; j++) {
    if (arr[j] < x) {
      i++;
      [arr[i], arr[j]] = [arr[j], arr[i]];
    }
  }
  [arr[r], arr[i + 1]] = [arr[i + 1], arr[r]];
  return i + 1;
}

function quickSort(p, r) {
  if (p < r) {
    let q = partition(p, r);
    quickSort(p, q - 1);
    quickSort(q + 1, r);
  }
}