def partition(arr, low, high):
    i = low - 1
    pivot = arr[high]
    for j in range(low, high):
        if arr[j] <= pivot:
            i = i+1
            arr[i],arr[j] = arr[j],arr[i]
    arr[i+1],arr[high] = arr[high],arr[i+1]# ???
    return i+1

def quick_sort(arr, low, high):
    if low < high:
        pi = partition(arr,low,high)
        quick_sort(arr, low, pi-1)
        quick_sort(arr, pi+1, high)
arr = [3,2,9,34,5,3,9,7,0,1]
quick_sort(arr, 0, len(arr)-1)
print(arr)