function sort(arr){ if(arr.length < 2){ return arr; } let i = arr.length - 1; let j = 0; let left = []; let right = []; while(j < i){ if(arr[j] < arr[i]){ left.push(arr[j]); } else { right.push(arr[j]); } console.log("pivot", arr[i]); console.log("left", left); console.log("right", right); j++; } return sort(left).concat(arr[i]).concat(sort(right)); } sort([2,6, 78, 86,34,56, 15, 90, 9, 25, 0, 64])