快速排序 和 分而治之（D&C）divde and conquer

• D&C 将问题逐步分解，找到最基本的情况为止
• 快速排序，随机的选择基准值，平均运行时间为**O(n*logn)**

def quicksort(array):
  if len(array) < 2:# base case, arrays with 0 or 1 element are already "sorted"
    return array
  else:# recursive case
    pivot = array[0]# sub-array of all the elements less than the pivot
    less = [i for i in array[1:] if i <= pivot]# sub-array of all the elements greater than the pivot
    greater = [i for i in array[1:] if i > pivot]
    return quicksort(less) + [pivot] + quicksort(greater)
print(quicksort([10, 5, 2, 3]))
    

## [2, 3, 5, 10]