确定比特的组合 [英] Determining combination of bits
本文介绍了确定比特的组合的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
说我有一个类似下面的词典
{1:''one'',2:''two'',4:''three'',8: ''四'',16:''五'等等......}
我给了一些数字,比如22,25和9.我想确定
键,2的幂,包含数字。
Ex。 22 = 16 + 4 + 2
25 = 16 + 8 + 1
9 = 8 + 1
....等等.. 。
如何获得这些密钥?
Say I have a dictionary like the following
{1:''one'',2:''two'',4:''three'',8:''four'',16:''five'', etc...}
and I am given some numbers, say 22, 25, and 9. I want to determine the
keys, powers of 2, that comprise the number.
Ex. 22 = 16+4+2
25 = 16+8+1
9 = 8+1
....etc...
How do I get these keys?
推荐答案
Sean Berry< sean< at> buildingonline.com>写道:
Sean Berry <sean <at> buildingonline.com> writes:
我想确定包含数字的密钥,2的幂。
Ex。 22 = 16 + 4 + 2
25 = 16 + 8 + 1
9 = 8 + 1
......等等......
I want to determine the keys, powers of 2, that comprise the number.
Ex. 22 = 16+4+2
25 = 16+8+1
9 = 8+1
...etc...
这听起来像家庭作业,所以我只想在这里给出一个提示:
This sounds suspiciously like a homework, so I''m just going to give a hint here:
导入数学
math.log(22,2)
4.4594316186372973 2 ** int(math.log(22,2))
16 2 ** int(math.log(22) - 16,2))
4 2 ** int(math.log(22 - 16 - 4 - 2,2))
2
import math
math.log(22, 2) 4.4594316186372973 2**int(math.log(22, 2)) 16 2**int(math.log(22 - 16, 2)) 4 2**int(math.log(22 - 16 - 4 - 2, 2)) 2
希望这是有帮助的。
史蒂夫
Hope this is helpful.
Steve
你没有'没有说明
数字有多大。如果它们保持较小(例如<数千)
你可以直接从字典中查找它们。
如果它们可以任意大,你必须使用bit
shifing和boolean& (和)。
听起来很像家庭作业,但我会给你一些提示。
1)使用位移运算符(>>)和布尔&
运算符来隔离整数中的每一位。
2)它将为零或一。建立一个
的清单,这些清单代表每一位代表两个人的b $ b。
Larry Bates
Sean Berry写道:
You didn''t say anything about how large the
numbers might get. If they stay small (e.g. <thousands)
you could just look them up directly from a dictionary.
If they can get arbitrarily large you must use bit
shifing and boolean & (and).
Sounds a lot like a homework assignment, but I''ll
give you some "hints".
1) Use bit shifting operator (>>) and boolean &
operator to isolate each bit in the integer.
2) It will be either zero or one. Build up a
list of these which will represent the power
of two that each one bit represents.
Larry Bates
Sean Berry wrote:
说我有一个类似下面的词典
{1:''one'',2: ''two'',4:''three'',8:''four'',16:''five''等......}
我给了一些数字,说22,25和9.我想确定构成数字的
键,2的幂。
Ex。 22 = 16 + 4 + 2
25 = 16 + 8 + 1
9 = 8 + 1
......等等......
我如何获得这些钥匙?
Say I have a dictionary like the following
{1:''one'',2:''two'',4:''three'',8:''four'',16:''five'', etc...}
and I am given some numbers, say 22, 25, and 9. I want to determine the
keys, powers of 2, that comprise the number.
Ex. 22 = 16+4+2
25 = 16+8+1
9 = 8+1
...etc...
How do I get these keys?
" Sean Berry" < SE ** @ buildingonline.com>在消息中写道
news:x3Qjd.121786
"Sean Berry" <se**@buildingonline.com> wrote in message
news:x3Qjd.121786
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