1、遞迴實現二叉查詢

def binary_search_recursion(lst,target,low,high):
    if high < low:
        return None
    middle = (low + high)//2
    if lst[middle] > target:
        return binary_search_recursion(lst,target,low,middle - 1)
    elif lst[middle] < target:
        return binary_search_recursion(lst,target,middle + 1,high)
    else:
        return middle
 

2、迴圈實現二叉查詢

def binary_search_loop(lst,target):
    low, high = 0,len(lst)-1
    while low <= high:
        middle = (low + high)//2
        if lst[middle] > target:
            high = middle -1
        elif lst[middle] < target:
            low = middle + 1
        else:
            return middle
    return None
 

3、bisect實現二叉查詢

import bisect

lst = [1,2,3,4,4,5,6]
print(bisect.bisect_left(lst,4))
print(bisect.bisect_right(lst,4))