# 二分查找
l01 = [i for i in range(1,101)]
start_index = 0
end_index = len(l01)-1
while start_index <= end_index:
mid_index = (start_index + end_index) // 2
if l01[mid_index] == 77:
print('找到了')
break
elif l01[mid_index] > 77:
end_index = mid_index - 1
else:
start_index = mid_index + 1
else:
print('没找到')
# 找到了
# binarysearch 创建一个函数 查找 是否存在
def binarysearch(l01,num):
start_index = 0
end_index = len(l01) - 1
while start_index <= end_index:
mid_index = (start_index + end_index) // 2
if l01[mid_index] == num:
return mid_index
elif l01[mid_index] > num:
end_index = mid_index - 1
else:
start_index = mid_index + 1
return -1
print(binarysearch([1,2,3,5,4,5,6,9,84,5,2,5,874,5,5],84))
# -1
# 寻找中间数是否对应 对应输出 84 不对应输出-1