quicksort matrix

sort.js

const t = require('tap')

const cases = [
  {
    matrix: [3, 5, 1, 3, 6, 2],
    cols: 1,
    result: [1, 2, 3, 3, 5, 6]
  },

  {
    matrix: [3, 5, 1, 3, 6, 2],
    cols: 2,
    result: [1, 3, 3, 5, 6, 2]
  }
]

function partition (arr, cols, startIndex, endIndex) {
  let index = startIndex
  let aux
  for (let i = index; i < endIndex; i += cols) {
    let swap
    // comparing logic
    for (let j = 0; j < cols; j++) {
      if (arr[i + j] < arr[endIndex + j]) {
        swap = true
        break
      }
    }

    if (!swap) {
      continue
    }

    // swap rows
    for (let j = 0; j < cols && i != index; j++) {
      aux = arr[i + j]
      arr[i + j] = arr[index + j]
      arr[index + j] = aux
    }

    index += cols
  }

  // swap pivot row
  for (let j = 0; j < cols; j++) {
    aux = arr[endIndex + j]
    arr[endIndex + j] = arr[index + j]
    arr[index + j] = aux
  }
  return index
}

function quickSort (arr, cols = 1, startIndex = 0, endIndex = arr.length - cols) {
  if (startIndex >= endIndex) {
    return
  }

  const pivotIndex = partition(arr, cols, startIndex, endIndex)

  quickSort(arr, cols, startIndex, pivotIndex - cols)
  quickSort(arr, cols, pivotIndex + cols, endIndex)
  return arr
}

for (let i = 0; i < cases.length; i++) {
  t.test(`#${i + 1}`, async (t) => {
    const a = [...cases[i].matrix]
    t.same(quickSort(a, cases[i].cols), cases[i].result)
    console.log({ cols: cases[i].cols })
    console.log(cases[i].matrix)
    console.log(a)
  })
}