def quicksort(arr):
    if len(arr) <= 1:
        return arr
    pivot = arr[len(arr) / 2]
    left = [x for x in arr if x < pivot]
    middle = [x for x in arr if x == pivot]
    right = [x for x in arr if x > pivot]
    return quicksort(left) + middle + quicksort(right)

def main():
    unsort_arr = [3,6,8,10,1,2,1]
    print 'before', unsort_arr
    print 'after', quicksort(unsort_arr)

if __name__ == '__main__':
    main()