Maths puzzle

[glasgowcyclist]

As if I didn't waste enough time at work, I've found this very addictive puzzle which is proving more difficult than it looks. (You can vary the size of the grid to make it harder)

Anyone have a method for winning?

https://nrich.maths.org/2526

 

[MartinQ]

Had a bit play with it earlier, and like most of the nrich stuff, it's well put together. I suppose that there isn't a simple winning strategy (it appears that the computer's response has some element of a random response), although obviously, there is a symmetry to start off with which cuts down the possibilities a bit.

I was losing my initial attempts where the computer won with squares which had sides length (root(3), root(4), ... i.e. they went along a couple and then up/down one). However, a bit of concentration was needed to stop this.

One of the key patterns to stop / try and get is three isolated like
--------*
----*
--------*
Then you're into a winning / losing end game as the opponent must counter with one to stop the obvious rotated square,
--------*
---*--------+
--------*
then you can put one in one of the other corners and there are two squares which could be formed, hence win / lose.
--------*
---*--------+
*-------*
So a simple strategy is to form / stop a "<" type pattern being formed without any opposing counters around it.

 

[Levo-Lon]

Thursday

 

[Fonze]

Been at it over the weekend still no joy .. mildly annoying me now ..

 

[nickyboy]

I can easily get to a point of not losing, but winning is taking a bit more concentration.

 

[Fonze]

Hahahaha ! Just done it using the triangle method ..

 

[Sandra6]

I won on about my 8th go.
No strategy, pure fluke.

 

[MartinQ]

Bad description, but here goes. Should work every time, hence the game becomes boring ...
a) Start in the middle
b) Next point is on the edge, directly N, S, E or W. Choose a direction so that the computer's first move is not in this half-board
c) Choose one of the two points to make a ">" shape. Choose the one that means the board quarter does not contain either of the first two computer choices.
d) Fairly easy to finish off now using a couple of simple end games as a ">" has been made in an empty board quadrant

With a bit of tweaking, should work for all boards with a center (sides are odd)., and putting it close to the centre (away from the edges) should work for even as well.

 

[midlife]

We used to play this as a kid in the 60's and 70's. lots of dots on a piece of paper and draw in the lines It was always a game to program in ALGOL as an exercise way back when LOL

 

[MartinQ]

We used to play this as a kid in the 60's and 70's. lots of dots on a piece of paper and draw in the lines It was always a game to program in ALGOL as an exercise way back when LOL

I was explaining the history of "hello world" to my son at the weekend (K&R, the "bible"). I think you've just top geeked me :-)

 

[Levo-Lon]

So it was Wednesday after all ..damn

 

[Fonze]

Bad description, but here goes. Should work every time, hence the game becomes boring ...
a) Start in the middle
b) Next point is on the edge, directly N, S, E or W. Choose a direction so that the computer's first move is not in this half-board
c) Choose one of the two points to make a ">" shape. Choose the one that means the board quarter does not contain either of the first two computer choices.
d) Fairly easy to finish off now using a couple of simple end games as a ">" has been made in an empty board quadrant

With a bit of tweaking, should work for all boards with a center (sides are odd)., and putting it close to the centre (away from the edges) should work for even as well.

Yep, got it now .l