算法图解-二分法

算法图解用Python来实现

1. def binary_search(list,item):
2.     low = 0 #用于跟踪其要在列表中查找到部分
3.     high = len(list)-1
4.     guess = list[mid]
5.     while low <= high:
6.         mid = (low+high)//2 #取整
7.         if guess == item: #找到了元素
8.             return mid
9.         if guess > item: #猜的数值大了
10.             high = mid-1
11.         else:                  #猜的数值小了
12.             low = mid+1
13.     return None #没有指定元素
15. if __name__== '__main__':
16.     my_list = [1,3,5,7,9,11，13,15]
17.     print(binary_search(my_list,5))
18.     print(binary_search(my_list,-1))