hacker.org

to the confused ones:
when someone wins, all the succeeding moves should be ignored.

Still confused... Tried many answers, all are wrong...

hhanger wrote:Still confused... Tried many answers, all are wrong...

patpat...

Some hint :p
There are 2 players play this game in turn and only wines or draws count.

hhanger wrote:Still confused... Tried many answers, all are wrong...

patpat

Since one space on the 9 space board is always taken by a 'O', there are 8 spaces to play, starting with 'X' taking the first turn.

Due to there being 8 spaces and each space either being taken by 'X' or 'O', I decided to represent entire games as one byte, with equal numbers of zeroes and ones (because each player takes 4 turns).

Since I don't want to spoil things I'll stop there. But I haven't found the answer with my method. I've tried accounting for reflections and also 'X' taking the center space in a second set of games, but still no dice. So I assume my methodology is flawed. But it looks right to me.

If someone who has solved it could just tell me if I'm wrong, then I'll approach it from a different angle. Otherwise I think I'm right and just have a bug in my approach.

I am bad at basically every aspect of maths :/
Also if this is considered saying too much then by all means delete this post.

zael wrote:Due to there being 8 spaces and each space either being taken by 'X' or 'O', I decided to represent entire games as one byte, with equal numbers of zeroes and ones (because each player takes 4 turns).

The fact that every player takes 4 turns is isn't really true. Games can be over before all players have taken 4 turns. Once a player has 3 in a row, the game finishes.

I forgot to mention that I was checking for a win after each turn. Thanks anyway.. it's probably my method that's wrong. It seemed right though

So what is the possibility that if I just make a program to randomly play games (and I count the draws) it'd give me the correct answer? I'm assuming since it's to 8 decimal places it'd take a lot of games to be accurate.

I got a question:

If these are the two boards:

O | O | X
X | X | X
O | X | O

O | O | X
X | X | X
X | O | O

And the person with X's wins at the very beginning, does this count as two games and two games won?

the second board you are giving can never be a valid end of the game. In this board, X is winning in 2 different ways. the game should have stopped after X has made the winning move.

Karian wrote:the second board you are giving can never be a valid end of the game. In this board, X is winning in 2 different ways. the game should have stopped after X has made the winning move.

I was trying to say that if this occurred:

O | |
X | X | X
O | |

Is that only one win or do I count all the extra moves after as a possible win as well?

I would assume not as they aren't really possible moves as the game would have ended and so no more moves are valid

Does this count as two games won or as one game won?

Isaev wrote:Does this count as two games won or as one game won?

2 games

I found the solution, but I am still confused whether the solution is actually correct. Plus the description of the challenge made me really confused. I didn't found it necessary to start a solved topic for this challenge.

The first player plays with circles(0) and the opponent plays with crosses(X). The board will have 8 free places which is indicated below.

1 | 2 | 3
4 | 0 | 5
6 | 7 | 8

now if the match is as following: 12345687. The number indicates the place where the X's and 0's are placed. So the first player plays a O at the centre, next the opponent plays a X at location 1, the first plays a 0 at location 2,... after 8 (including the opening move) moves we have the current situation:

X | O | X
O | O | X
O | | X

this means the game is over, the opponent won. But the description states the opponent can't win, because placing the first move at the centre is a sure way to win. In the real world this would of course not happen, because the first player could easily block the 3 X's and make a draw of the situation. Judging from the program I wrote this situation is placed in the category of draws. But I didn't found that to be according to the given task.

vjeetje wrote:this means the game is over, the opponent won. But the description states the opponent can't win, because placing the first move at the centre is a sure way to win. In the real world this would of course not happen, because the first player could easily block the 3 X's and make a draw of the situation. Judging from the program I wrote this situation is placed in the category of draws. But I didn't found that to be according to the given task.

The description states that if you play intelligently, it is a sure win/draw. It is just an introduction to the problem, an explanation why the first move is in the center.
The problem resolves around random games after this point. Surely, in a random match, the second player still has a chance, so there is no reason to count this as a draw.