快速排序

快速排序

#快速排序

def quick_sort(alist , first=0 ,last=None):
    if last is None:
        last = len(alist) - 1
    if first >= last:
        return 
    mid_val = alist[first]
    low=first
    high = last
    while low < high:
        while low < high and alist[high] >= mid_val:
            
            high -= 1
        alist[low],alist[high] = alist[high],alist[low]
        while high > low and alist[low] < mid_val:
            low += 1
        alist[high],alist[low] = alist[low],alist[high]
    alist[low],mid_val= mid_val,alist[low]
    quick_sort(alist,first,low-1)
    quick_sort(alist,low+1,last)

if __name__=="__main__":
    l = [23 ,54 ,12 ,8, 48,16,88,3,36]
    print(l)
    quick_sort(l)
    print(l)