20200129, 17:07  #1 
Dec 2019
Kansas
2^{4} Posts 
February 2020

20200205, 09:19  #2 
Oct 2017
76_{10} Posts 
Some remarks for comparison, testing,...
The exact value of the expected number of moves of the given example (Milton Bradley game) containing 9 ladders and 10 snakes is: Numerator: 225837582538403273407117496273279920181931269186581786048583 Denominator: 5757472998140039232950575874628786131130999406013041613400 computed by Althoen, King, Schilling without using floats (!!!) in 1993. That is = 39,225122308234960369445... My code using simple double precision flaoting point values (64 Bit) yields 39,225122308234909. So 64 bit should be sufficient for the challenge  perhaps not for the „*“. For the challenge itself I use brute force. Two days ago I have submitted a combination of pairs yielding 66,97870454786... Meanwhile I have found 66,9787048756..., but I am far away from *. Last fiddled with by Dieter on 20200205 at 09:21 
20200206, 07:16  #3 
Jul 2015
3^{2} Posts 
So far, I got 15 different solutions.
The speed of my code is approximately 1 solution / 3~4 hours. (I used bruteforce method with a little bit of optimization.) Can I eventually get the bonus '*' in February? I don't know. Below is the obtained solutions and the errors until now. Solutions (Expected moves) Errors 66.978705461630 0.000000454075 66.978704620197 0.000000387358 66.978705335723 0.000000328168 66.978704680018 0.000000327537 66.978704698700 0.000000308855 66.978704705772 0.000000301783 66.978705293440 0.000000285885 66.978705290182 0.000000282627 66.978705240145 0.000000232590 66.978704841683 0.000000165872 66.978705149669 0.000000142114 66.978704904408 0.000000103147 66.978705103018 0.000000095463 66.978705033187 0.000000025632 66.978705009608 0.000000002053 
20200206, 09:27  #4  
Oct 2017
2^{2}·19 Posts 
Quote:
Meanwhile my best is 66,9787050875 (error = 8*10^(–8). But it is a search of the needle in the haystack (is that a germanism?). If I have a good value and if I change one parameter in one [source,target] pair, I get a totally different bad value. So I let work 8 threads and I am happy that we have a leap year. 

20200207, 09:56  #5  
"Kebbaj Reda"
May 2018
Casablanca, Morocco
5·11 Posts 
Quote:
Oddly it does not exist in my native language ?, "Rachid naimi" Can you confirm that !. If it has an equivalent? For those who didn't know the game like me, here is a link. Its helped me better understand the question: https://www.crazygames.com/game/snakesandladders 

20200211, 20:55  #6 
"Hugo"
Jul 2019
Germany
2·3·5 Posts 
May I ask you for a little help? The article by Althoen, King and Schilling states: The expected playing time for a 100square game played with a sixsided die (...neither snakes nor ladders), i.e., the empty board. It is almost exactly 33 moves.
I cannot reproduce this value, but get slightly more: 33.3... What expected game time do you get for the empty board? 
20200211, 21:29  #7  
Sep 2017
2^{3}·3^{2} Posts 
Quote:


20200211, 21:50  #8 
"Hugo"
Jul 2019
Germany
36_{8} Posts 
Thanks!
Well then I don't have to worry about it anymore. I got both with the random simulation, with which I can recalculate the original game quite accurately, and with an exact calculation the approx. 33.333 ... The exact result should be Code:
77793808048991155069512637767746406705805011749411165293240199952210986407 / 2333814241469732031952625840042216151324387397379954245052697639351484416 = 33.33333333333337075608827723... 
20200211, 21:51  #9  
Sep 2017
2^{3}×3^{2} Posts 
Quote:


20200212, 19:04  #10 
Oct 2017
2^{2}×19 Posts 
The solvers list has been updated. There is only one solver with „*“.
Meanwhile my best combination has an error of 1,555*10**(9). Has anyone of you significantly better values? 
20200212, 22:17  #11 
Sep 2017
2^{3}×3^{2} Posts 
There are ~100^{20} possible combinations.
It is like the puzzlemaster is saying "I have a combination in mind, can you find it?" There doesn't seem to be any clue as to how to find it. And we all have been trying for the last 2 weeks to find it by random search. Good luck! 
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