Tricky but not impossible.

# Guessing digits

**anon-ymous**#2

It seems quite hard for me. I must be missing something, since my solution fails the last validator, while passing the provided test cases and anything I could come up with.

**Sylver**#3

Hello,

The problem seems insufficiently explained. What happens during a round? Each player gives a pair of digits? Does that mean the number of rounds necessary is the maximum number of rounds to bruteforce the problem (because a player can give the right one first with some luck)?

Also, how can it be IMPOSSIBLE to guess a pair of digits?

Given that we know that a and b are between 1 and 9 included, the number of combinations is small (less than 81).

For instance in test case 8, the sum of digits is 11 and the product 24.

Possible combinations to get a sum of 11: (6,5) (7,4) (8,3) (9,2) => 4 turns

Possible combinations to get a product of 24: (3,8) (4,6) => 2 turns

But the expected result is IMPOSSIBLE, why ?

Is that a mistake and IMPOSSIBLE means that Maggie gave the wrong numbers on the paper and test case 8 is wrong?

Thank you in advance !

Cheers.

**_CG_Thibaud**#4

Itâ€™s a logical problem.

First, she asks Burt if he knows the digits from the set of equations. If there are too many possibilities, he canâ€™t know the right answer, so he has to pass. Then, itâ€™s Sarahâ€™s turn to guess with her own informations.

The trick in this problem is that â€śpassingâ€ť constitutes an important information for the other player.

IMPOSSIBLE means that they can guess the pair without taking the risk to fail after the rounds above.

**NonoLeRobot**#5

Hi,

My solution passes all the tests but the **Validator 2** failed.

Can someone give me a clue for this validator ?

Thx

**_CG_Thibaud**#6

couldnâ€™t find a useful hint to tell, so I sent you the validator.

Let us know what failed

**NonoLeRobot**#7

Hi _CG_Thibaud,

Itâ€™s all right, I managed to pass all the validators

My solution was really too complicated. I wasnâ€™t inspiredâ€¦

I wrote a better one from scratch that Iâ€™ve published.

Thank you so much

P.S. : Your email was sent to an address I changed a long time ago.

Do you know someone who can fix that ?

**_CG_Thibaud**#8

cool news.

About the email, itâ€™s the one related to your Discourse account, created the first time you entered the CG forum. You can change it here: https://www.codingame.com/forum/u/NonoLeRobot/preferences/account

**imq**#10

Provided Burt and Sarah have many possibilities to guess in the first round. Who will be the first to guess like test 3? What is the rule to guess a digit among many possibilities?

Thanks.

**RoboStac**#11

On each turn a player only has two possible actions. They can either say the correct digits or pass to the next player.

**imq**#12

I donâ€™t quite understand the flow and the rule to make a guess. There are many possibility to guess. Which one will be chosen to guess first. Could you please elaborate about Test 3.

Given Burt has sum 7 while Sarah has product 6.

The possibilities of Burt are (1,6) (2,5) (3,4) while Sarahâ€™s are (1,6) (2,3) that resulting (1,6) SARAH 3. What is the flow of the game.

Many thanks!

**NonoLeRobot**#13

Iâ€™ve found how to change it.

My old mail was still used for the notificationsâ€¦

Thx Thibaud