二分法查找主要的作用就是查找元素
规则. 掐头结尾取中间, 必须是有序列
# 二分法查找 (需要你明白和掌握)
# lst = [1,3,5,7,12,36,68,79]
# n = int(input("请输入一个数"))
#
# left = 0
# right = len(lst) - 1
#
# while left <= right:
# mid = (left + right)//2
# if n > lst[mid]:
# left = mid + 1
# elif n < lst[mid]:
# right = mid - 1
# else:
# print("存在")
# break
#
# else:
# print("不存在")
# 递归二 (需要你明白和掌握)
# def func(n, lst, left, right): # 递归找到什么是可以变的. 什么是不可以变的
# if left <= right:
# mid = (left + right) // 2
# if n > lst[mid]:
# left = mid + 1
# return func(n, lst, left, right)
# elif n < lst[mid]:
# right = mid - 1
# return func(n, lst, left, right) # 递归如果有返回值. 所有调用递归的地方必须写return
# else:
# print("找到了")
# return mid # 难点
# else:
# print("找不到")
# return -1
#
# n = int(input("请输入你要查找的数:"))
# lst = [1,3,55,98,37,41,2,5,1,4]
# ret = func(n, lst, 0, len(lst)-1) # 78
# print(ret)
# 最快的查找
lst = [1,3,55,98,37,41,2,5,1,4]
new_lst = []
for i in range(99):
new_lst.append(0)
for i in lst: # 1,3,55,98
new_lst[i] = 1
print(new_lst)
i = int(input('请输入你要找的数据'))
if new_lst[i] == 0: # 1次
print("不存在")
else:
print("存在")
