function processData(arr) {
  //Enter your code here
  const pivot = arr.length - 1;
  let i = -1;
  
  if(arr.length <= 1) return arr

  for (let j = 0; j < arr.length; j++) {
    
    if (arr[j] < arr[pivot]) {
      //we increment i
      i++;

      //we swamp elements
      const toSwamp = arr[i];
      arr[i] = arr[j];
      arr[j] = toSwamp;
     
    }

    if (j === pivot) {
      const toSwamp = arr[i + 1];
      arr[i + 1] = arr[pivot];
      arr[pivot] = toSwamp;
    
    }
  }
  
  console.log(arr)
  return processData(arr.slice(0, i+1)).concat(processData(arr.slice(i+1, pivot+1)))
}