https://www.theguardian.com/science/2023/jul/10/can-you-solve-it-are-you-brainy-at-binary

On Tue, 11 Jul 2023 00:57:34 +1000
dxforth <dxforth@gmail.com> wrote:

> https://www.theguardian.com/science/2023/jul/10/can-you-solve-it-are-you-brainy-at-binary

I don't usually do puzzles, but did read the headline:

'Prime Minister Rishi Sunak stands at the door of 10 Downing Street, London,
in June 2023, as numbers stuck to the door spell out 'London Tech Week' in
binary code, ahead of a garden reception for London Tech Week.'

And this was was enough to guess that the 24 bits shown do not spell that
much.

$ gforth
Gforth 0.7.3, Copyright (C) 1995-2008 Free Software Foundation, Inc.
Gforth comes with ABSOLUTELY NO WARRANTY; for details type `license'
Type `bye' to exit
2 base ! ok
01001100 emit L ok
01010100 emit T ok
01010111 emit W ok

Jan Coombs
--

> https://www.theguardian.com/science/2023/jul/10/can-you-solve-it-are-you-brainy-at-binary
„Devise a binary code that translates ABACAB into a string consisting of only 9 bits”

What about:
A - 0
B - 10
C - 11
ABACAB = 010011010

No ambiguity, correct?

On 11/07/2023 5:25 am, Zbig wrote:
>> https://www.theguardian.com/science/2023/jul/10/can-you-solve-it-are-you-brainy-at-binary
> „Devise a binary code that translates ABACAB into a string consisting of only 9 bits”
>
> What about:
> A - 0
> B - 10
> C - 11
> ABACAB = 010011010
>
> No ambiguity, correct?

And the second puzzle?

On 11/07/2023 3:52 am, jan Coombs wrote:
> On Tue, 11 Jul 2023 00:57:34 +1000
> dxforth <dxforth@gmail.com> wrote:
>
>> https://www.theguardian.com/science/2023/jul/10/can-you-solve-it-are-you-brainy-at-binary
>
> I don't usually do puzzles, but did read the headline:
>
> 'Prime Minister Rishi Sunak stands at the door of 10 Downing Street, London,
> in June 2023, as numbers stuck to the door spell out 'London Tech Week' in
> binary code, ahead of a garden reception for London Tech Week.'
>
> And this was was enough to guess that the 24 bits shown do not spell that
> much.
>
> $ gforth
> Gforth 0.7.3, Copyright (C) 1995-2008 Free Software Foundation, Inc.
> Gforth comes with ABSOLUTELY NO WARRANTY; for details type `license'
> Type `bye' to exit
> 2 base ! ok
> 01001100 emit L ok
> 01010100 emit T ok
> 01010111 emit W ok

The only puzzle in current British politics is finding difference where none
exists. OTOH anyone who has programmed should be able to solve these...

> >> https://www.theguardian.com/science/2023/jul/10/can-you-solve-it-are-you-brainy-at-binary
> > „Devise a binary code that translates ABACAB into a string consisting of only 9 bits”
> >
> > What about:
> > A - 0
> > B - 10
> > C - 11
> > ABACAB = 010011010
> >
> > No ambiguity, correct?
> And the second puzzle?

What about:
A - 0
B - 111
C - 11
D - 01

ABACADABA = 011101100101110

On 11/07/2023 09:27, Zbig wrote:
>>>> https://www.theguardian.com/science/2023/jul/10/can-you-solve-it-are-you-brainy-at-binary
>>> „Devise a binary code that translates ABACAB into a string consisting of only 9 bits”
>>>
>>> What about:
>>> A - 0
>>> B - 10
>>> C - 11
>>> ABACAB = 010011010
>>>
>>> No ambiguity, correct?
>> And the second puzzle?
>
> What about:
> A - 0
> B - 111
> C - 11
> D - 01
>
> ABACADABA = 011101100101110

No, for example 0111 could be AB or DC. You need two 3-digit codes.

--
Cheers
Clive

> No, for example 0111 could be AB or DC. You need two 3-digit codes.

Oh, overlooked… :(

OK, so the final solution is:
A - 0
B - 11
C - 101
D - 111

ABACADABA -- 011010101110110

On 11/07/2023 10:16, Zbig wrote:
>> No, for example 0111 could be AB or DC. You need two 3-digit codes.
>
> Oh, overlooked… :(
>
> OK, so the final solution is:
> A - 0
> B - 11
> C - 101
> D - 111
>
> ABACADABA -- 011010101110110

Not quite - 111111 could be DD or BBB.

--
Cheers
Clive

wtorek, 11 lipca 2023 o 13:03:50 UTC+2 Clive Arthur napisał(a):
> On 11/07/2023 10:16, Zbig wrote:
> >> No, for example 0111 could be AB or DC. You need two 3-digit codes.
> >
> > Oh, overlooked… :(
> >
> > OK, so the final solution is:
> > A - 0
> > B - 11
> > C - 101
> > D - 111
> >
> > ABACADABA -- 011010101110110
> Not quite - 111111 could be DD or BBB.

Look at the conditions of the exercise — the task was to code ABACADABA
unambiguous way, and not „every possible” string containing A, B, C, D.

On 11/07/2023 12:24, Zbig wrote:
> wtorek, 11 lipca 2023 o 13:03:50 UTC+2 Clive Arthur napisał(a):
>> On 11/07/2023 10:16, Zbig wrote:
>>>> No, for example 0111 could be AB or DC. You need two 3-digit codes.
>>>
>>> Oh, overlooked… :(
>>>
>>> OK, so the final solution is:
>>> A - 0
>>> B - 11
>>> C - 101
>>> D - 111
>>>
>>> ABACADABA -- 011010101110110
>> Not quite - 111111 could be DD or BBB.
>
> Look at the conditions of the exercise — the task was to code ABACADABA
> unambiguous way, and not „every possible” string containing A, B, C, D.

0 11 0 101 0 111 0 11 0 = ABACADABA
but also
0 11 0 101 0 11 101 10 = ABACABC?

OK, the second one throws an error, so you'd need to backtrack, but
you'd get the result in the end.

Whereas

A - 0
B - 11
C - 101
D - 100

0 11 0 101 0 100 0 11 0 = ABACADABA is unambiguous.

--
Cheers
Clive

> 0 11 0 101 0 111 0 11 0 = ABACADABA
> but also
> 0 11 0 101 0 11 101 10 = ABACABC?

But what '?' means? It means there's not recognized „leftover”.

> OK, the second one throws an error, so you'd need to backtrack, but
> you'd get the result in the end.
>
> Whereas
> A - 0
> B - 11
> C - 101
> D - 100
>
> 0 11 0 101 0 100 0 11 0 = ABACADABA is unambiguous.

But exactly because you've got a '?' in the second case it tells you
that second attempt is invalid — and only the first „decoding attempt”
is valid. So still no ambiguity.

On 11/07/2023 14:03, Zbig wrote:
>> 0 11 0 101 0 111 0 11 0 = ABACADABA
>> but also
>> 0 11 0 101 0 11 101 10 = ABACABC?
>
> But what '?' means? It means there's not recognized „leftover”.
>
>> OK, the second one throws an error, so you'd need to backtrack, but
>> you'd get the result in the end.
>>
>> Whereas
>> A - 0
>> B - 11
>> C - 101
>> D - 100
>>
>> 0 11 0 101 0 100 0 11 0 = ABACADABA is unambiguous.
>
> But exactly because you've got a '?' in the second case it tells you
> that second attempt is invalid — and only the first „decoding attempt”
> is valid. So still no ambiguity.

You must work for Microsoft :-)

--
Cheers
Clive

wtorek, 11 lipca 2023 o 18:43:56 UTC+2 Clive Arthur napisał(a):
> On 11/07/2023 14:03, Zbig wrote:
> >> 0 11 0 101 0 111 0 11 0 = ABACADABA
> >> but also
> >> 0 11 0 101 0 11 101 10 = ABACABC?
> >
> > But what '?' means? It means there's not recognized „leftover”.
> >
> >> OK, the second one throws an error, so you'd need to backtrack, but
> >> you'd get the result in the end.
> >>
> >> Whereas
> >> A - 0
> >> B - 11
> >> C - 101
> >> D - 100
> >>
> >> 0 11 0 101 0 100 0 11 0 = ABACADABA is unambiguous.
> >
> > But exactly because you've got a '?' in the second case it tells you
> > that second attempt is invalid — and only the first „decoding attempt”
> > is valid. So still no ambiguity.
> You must work for Microsoft :-)

Forgive me for being contrary, but if you insist your decode 011010101110110
as ABACABC? is „correct” then you could decode that to ?CACBABA as well — or
to literally anything using '?' as a „filler character” for any part of the „binary code”.

The same way I could decode your „binary” as ?CACAAABA. Why not, when having
such „joker” in the sleeve?

Either we agree, than „ambiguity” means possibility to decode „binary” to some other
string which comprises *the selected letters* only — or, if we attach '?' to them as
„any other”, we can do about anything.

On 11/07/2023 19:56, Zbig wrote:

> Forgive me for being contrary,

<snipped>

No, the solution I gave is unambiguous (and obvious to those 'skilled in
the art'). Less output, more input, and you might learn.

--
Cheers
Clive

On 12/07/2023 2:43 am, Clive Arthur wrote:
> On 11/07/2023 14:03, Zbig wrote:
>>> 0 11 0 101 0 111 0 11 0 = ABACADABA
>>> but also
>>> 0 11 0 101 0 11 101 10 = ABACABC?
>>
>> But what '?' means? It means there's not recognized „leftover”.
>>
>>> OK, the second one throws an error, so you'd need to backtrack, but
>>> you'd get the result in the end.
>>>
>>> Whereas
>>> A - 0
>>> B - 11
>>> C - 101
>>> D - 100
>>>
>>> 0 11 0 101 0 100 0 11 0 = ABACADABA is unambiguous.
>>
>> But exactly because you've got a '?' in the second case it tells you
>> that second attempt is invalid — and only the first „decoding attempt”
>> is valid. So still no ambiguity.
>
> You must work for Microsoft :-)

Puzzle rules:

"Every letter has its own unique code, and these are the only codes.
The code is not ambiguous."

BTW I sent the puzzle to someone who worked at Microsoft. Still waiting
for a response :)

> Less output, more input, and you might learn.

Medice, cura te ipsum.

Cheers! :)