quick_sort-arrays-2.js

let array = [5, 5, 7, 2, 9, 1, 1, 1, 8, 8, 2, 4, -100, -2, 4, 3, 2, 8, 100, 9, 1];

function quickSort(array) {
  if (array.length <= 1) return array;

  let minIndex = 0;
  let maxIndex = array.length - 1;

  let middleArray = [];
  let lessArray = [];
  let moreArray = [];

  let middleIndex = Math.floor(array.length / 2);
  let middleElem = array[middleIndex];

  while (minIndex < maxIndex) {
    if (array[minIndex] > middleElem) {
      moreArray.push(array[minIndex]);
    } else if (array[minIndex] == middleElem) {
      middleArray.push(array[minIndex]);
    } else if (array[minIndex] < middleElem) {
      lessArray.push(array[minIndex]);
    }

    if (array[maxIndex] > middleElem) {
      moreArray.push(array[maxIndex]);
    } else if (array[maxIndex] == middleElem) {
      middleArray.push(array[maxIndex]);
    } else if (array[maxIndex] < middleElem) {
      lessArray.push(array[maxIndex]);
    }

    ++minIndex;
    --maxIndex;
  }

  for (let i = 0; i < array.length; i++) {}

  return [...quickSort(lessArray), ...middleArray, ...quickSort(moreArray)];
}

console.log(quickSort(array));