非递归二分法

lst = []
for i in range(1,5000,3):
    lst.append(i)
num = int(input('请输入一个数:'))
left = 0
right = len(lst) - 1
count = 0
while left <= right:
    count += 1
    mid = (right + left) // 2
    if num < lst[mid]:
        right = mid - 1
    elif num > lst[mid]:
        left = mid + 1
    else:
        print('find it')
        break
else:
    print('can not find it')
print(count)

lst = []
for i in range(1,5000,3):
    lst.append(i)
num = int(input('请输入一个数:'))
left = 0
right = len(lst) - 1
count = 0
while left <= right:
    count += 1
    mid = (right + left) // 2
    if num < lst[mid]:
        right = mid - 1
    elif num > lst[mid]:
        left = mid + 1
    else:
        print('find it')
        break
else:
    print('can not find it')
print(count)