var quickSort = function(nums) {

if (!nums) return []

if (nums.length < 2) return nums

let pivot = Math.floor(nums.length / 2)

const leftNums = []

const rightNums = []

const center = nums[pivot]

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

if (center < nums[i]) {

leftNums.push(nums[i])

} else if (i !== pivot) {

rightNums.push(nums[i])

}

}

return quickSort(leftNums).concat([center], quickSort(rightNums))

}