Recursive thinking, dichotomy

Dichotomy (recursive instance)

2 achieved by a recursive algorithm to find points in order from the list a = [1,3,4,6,7,8,9,11,15,17,19,21,22,25,29,33,38,69,107 ] find the specified value.

a = [1,3,4,6,7,8,9,11,15,17,19,21,22,25,29,33,38,69,107]
def two(start,end,n,d_list):
    if start<end:
        mid = (start+end)//2
        if d_list[mid] >n:
            two(start,mid,n,d_list)
        elif d_list[mid] < n:
            two(mid,end,n, d_list)
        else:
            print('找到了',d_list[mid],mid)
    else:# 假设start=9,end=9, 那d_list[9:9]已经取不到值了，在这种情况下，只能说明，要找的这个值不在这个列表里
        print('找不到这个数据')
two(0,len(a),22,a)

总结：
    在函数的形参位置放一些数据，有利于优化代码量