Talk:24 game

Purpose

What's the theoretical or practical interest in this task? I'd be interested in a program that enumerated all the 4-tuples that have solutions or determined whether a given 4-tuple had a solution, but we've already got tasks for getting input from the user, parsing arithmetic expressions, and so on. —Underscore 19:22, 31 October 2009 (UTC)

Umm,

1. Playing the game.
2. We have a gazillion sorts for example, (some are very impractical); so we can stand some repetition.
3. We don't have many games, (of any description). Some site grazers might be attracted just by the word 'game'.
4. The input checking is novel.
5. The task is more than the some of its parts! (We have tasks covering most statement types, and it would not make sense to use that as a reason for not doing any composite task).
6. Prelude to possibly another task to solve the game.

(I don't like to write a task until I have a solution and so can better gauge its suitability, and so write a better task description). --Paddy3118 20:57, 31 October 2009 (UTC)

Without any official guidelines as to what's an appropriate Rosetta task and what isn't, I suppose it's all completely subjective, so I can't very well argue with you. Adding more games isn't such a bad idea; RCRPG is interesting from an implementation point of view but sorely lacking in the fun department. I wonder how hard it is to write a minimal Pong clone. —Underscore 22:24, 31 October 2009 (UTC)

Very easy, with modern hardware and programming languages.

FWIW, this task does strike me as being a somewhat useful one. I used to have a similar time waster game when I was a teen where you got 4 numbers and a goal, the end. (Except for the variable goal, identical to this task.) -- Eriksiers 02:23, 1 November 2009 (UTC)

Since there really is no body of multiple individuals to give any sort of official policy, any concept of "official" falls to whatever I say by fiat. Which sucks, because I'm nowhere near as knowledgeable on programming as many of RC's contributors are, regular or not. All I really know is that I have a good mental picture of the kinds of roles I want to the site to fill. Beyond that, I don't pretend to have expertise; Many of my early ideas and attempts at trying to come up with task descriptions were too specific, enforcing my own limited view of programming on the examples, so I've learned to stand back. I step in from time to time if I see discussion heading in a direction counter to where I'd like the site to go, but that's about it.

As for "redundant" tasks, it doesn't bother me. In fact, I can think of ways to take advantage of it, such as category tagging individual examples with techniques, features or principles they may illustrate, to offer another way to browse and search the site, and to be more illustrative of alternate approaches. --Michael Mol 17:12, 1 November 2009 (UTC)

Methinks you're turning into a Python-esque BDFL ;-)

--Paddy3118 18:49, 1 November 2009 (UTC)

It's also practical; I've got one paid 50hr/wk job coding, one 30+hr/wk job taking care of an elderly family member, and one 50hr/wk job sleeping. Not much time left to micromanage RC, as well as have any [other] hobbies. :) --Michael Mol 23:13, 1 November 2009 (UTC)

A game player was not too difficult so I created it as a separate (but linked), task. --Paddy3118 04:52, 1 November 2009 (UTC)

Autohotkey and Untested

Does untested mean that it has not been shown to run? If so, could we restrict ourselves to examples that have at least been run? (Or do you mean: "insufficiently tested but has at least been run")? --Paddy3118 05:37, 11 November 2009 (UTC)

I also agree (that the program should at least run (execute).   There have been entries that do not work at all for the computer programming language (category) entry that it was entered for.   It's a whole 'nother can of worms.   -- Gerard Schildberger (talk) 01:56, 10 May 2016 (UTC)

Floating point

Is recommending floating point wise? Precision and rounding errors would seem to defeat the purpose of preserving remainders. --Michael Mol 03:58, 8 December 2009 (UTC)

It isn't rigorous, (I'm an engineer, not a theoretical mathematician captain), but with the restricted range of single digit numbers, the given operators, and the precision of most FP implementations on a PC; I don't think it will matter. --Paddy3118 07:12, 8 December 2009 (UTC)

Certainly rationals are a better choice than floating point for this type of task, but I think you should be able to use floating point safely so long as you say something like if abs(ans - 24) < 1e-6 instead of if ans == 24. It's considered good practice, in general, to never test a floating-point variable for exact equality. That said, I'm at a loss for an input that the Python program would wrongly reject, so maybe floating point is better than I think it is. —Underscore (Talk) 12:49, 8 December 2009 (UTC)

If someone can exhibit a solution that a floating-point version won't find, that's when action becomes necessary. However, when I try out likely problems then I find I still cannot trigger any issues. For example:

<lang tcl>$ tclsh8.5

% expr {(((1.0/3.0)*9.0)*8.0) - 24.0} 0.0</lang>Despite a definitely non-representable intermediate (I know the implementation) the answer is exact. I just can't trigger the problem for anything that might be a solution. (Non-solutions… who cares about them?) Rationals might be theoretically better, but IEEE double seems good enough here. –Donal Fellows 13:32, 8 December 2009 (UTC)

You mentioned in Talk:24_game_Player#Should_we_enumerate_all_solutions.3F that it was practicable to identify all 7,860 solutions. That sounds like a pretty small test set. (Or am I misunderstanding your description of the enumeration?) --Michael Mol 18:49, 8 December 2009 (UTC)

Hi Donal, you might try 3 3 8 8 in the TCL example. Floating point won't work for this in Python. --Paddy3118 14:18, 15 February 2011 (UTC)

3 3 8 8 has different values depending on the Tcl versions it seems <lang>:> /opt/tcltk_8.0.3/bin/tclsh8.0

% expr 8.0 / ( 3.0 - 8.0 / 3.0 ) 24.0 %

> /opt/tcltk_8.3.4/bin/tclsh

% expr 8.0 / ( 3.0 - 8.0 / 3.0 ) 24.0 %

> /opt/tcltk_8.4.13/bin/tclsh

% expr 8.0 / ( 3.0 - 8.0 / 3.0 ) 24.0 %

> /opt/TWWfsw/bin/tclsh8.5

% expr 8.0 / ( 3.0 - 8.0 / 3.0 ) 23.99999999999999 %</lang> --Paddy3118 14:34, 15 February 2011 (UTC)

One potential problem with floating point, when you get to more than 4 digits, is that in some languages (not Python), division by 0.0 evaluates to infinity (which can be divided by again to get 0), instead of raising an error, so for example, this in Ruby: 3.0 * (8.0 + 4.0 / (2.0 / (5.0 - 5.0))) results in 24.0, which you might not want to allow. But I agree that this is not an issue with only 4 digits. --Spoon! 14:16, 8 December 2009 (UTC)

Precisely. That's why it matters that it is a “24-game player”. A solution with computation using rationals would be interesting though. –Donal Fellows 14:57, 8 December 2009 (UTC)

Does the Perl code work?

I have tryed to run the Perl code, and it seems that it doesn't recognise when the correct answer is given. --Blue Prawn 00:42, 26 January 2010 (UTC)

Scala only presenting numbers with solutions

I note that the impressive Scala example seems to only present a set of numbers guaranteed to have a solution. i can't help but think that from playing the game, some of the fun is lost, as we quite enjoyed trying the toughies - not knowing if they actually had a solution or not as most numbers do. I guess they don't have to add much for a solution to 24 game Player. --Paddy3118 06:43, 28 April 2010 (UTC)

I couldn't quite understand fully the meaning of the penultimate statement as it appears it may be missing an Oxford comma.   Most numbers don't have a solution.   (See the next talk section).   -- Gerard Schildberger (talk) 08:04, 15 March 2017 (UTC)

REXX only presenting digits with at least one solution

I have programmed the REXX example to also only present a set of digits that have a solution   (as does Scala).

From the task preamble:

The goal is for the player to enter an expression that (numerically) evaluates to 24. 

Nowhere does it imply that an impossible set of digits is to be determined and, somehow, the user is supposed to   not   enter a solution;   as it is, no computer programming entry checks for a   not possible   answer for a solution.

When presented with the digits     1 7 6 8,     what should a carbon-based life form (user) respond with for an answer (which is a non-solution)?

No such animal?
N/A
there ain't one
not possible
nope.
I give up.
I don't know
Please tell me the answer!!!
bupkis

Some of the solvable digits (numbers) are hard enough to find a solution, and presenting an unsolvable problem doesn't seem to be fair or realistic, since this is a game, not a riddle, and the game is to find a solution, not   "none-solutions".

unsolvable solutions for the 24 game

Of the   6,561   legal/valid numbers (with four digits) that can be presented   (numbers without any zeroes),   2,501   1,263   are   unsolvable   (that represents about   38%   19%   unsolvable).   This presumes that the REXX program correctly solved all possible (allowable) numbers.

(I have a complete list of the 1,501 unsolvable numbers for the 24 game.)   -- Gerard Schildberger (talk) 08:04, 15 March 2017 (UTC)
I found an error in the way the output file was massaged and created a list from the post-edited output file.

I have an updated complete list of the 1,263 unsolvable numbers for the 24 game.     -- Gerard Schildberger (talk) 00:27, 5 January 2019 (UTC)

Here are the formatted (indexed) unsolvable numbers (the order of the digits are preserved) for the 24 game:

   1► 1111 1112 1113 1114 1115 1116 1117 1119 1121 1122 1123 1124 1125 1131 1132 1133 1141 1142 1151 1152
  21► 1159 1161 1167 1171 1176 1177 1178 1179 1187 1189 1191 1195 1197 1198 1199 1211 1212 1213 1214 1215
  41► 1221 1222 1223 1231 1232 1241 1251 1299 1311 1312 1313 1321 1322 1331 1355 1411 1412 1421 1463 1499
  61► 1511 1512 1519 1521 1535 1553 1557 1558 1575 1577 1585 1591 1611 1617 1634 1643 1667 1671 1676 1677
  81► 1678 1687 1711 1716 1717 1718 1719 1755 1757 1761 1766 1767 1768 1771 1772 1775 1776 1777 1778 1781
 101► 1786 1787 1791 1817 1819 1855 1867 1871 1876 1877 1891 1899 1911 1912 1914 1915 1917 1918 1919 1921
 121► 1929 1941 1947 1949 1951 1957 1961 1967 1971 1974 1975 1976 1981 1989 1991 1992 1994 1998 1999 2111
 141► 2112 2113 2114 2115 2119 2121 2122 2123 2131 2132 2141 2151 2177 2191 2199 2211 2212 2213 2221 2222
 161► 2226 2231 2262 2279 2297 2299 2311 2312 2321 2334 2343 2411 2433 2511 2555 2556 2565 2599 2622 2655
 181► 2677 2711 2717 2721 2729 2767 2771 2774 2776 2777 2779 2792 2797 2799 2825 2852 2911 2919 2927 2929
 201► 2944 2959 2972 2977 2978 2979 2987 2991 2992 2995 2997 2999 3111 3112 3113 3121 3122 3131 3146 3155
 221► 3164 3211 3212 3221 3234 3243 3311 3324 3342 3358 3385 3416 3423 3432 3461 3467 3476 3488 3511 3515
 241► 3517 3538 3551 3555 3571 3577 3583 3614 3641 3647 3674 3715 3717 3746 3751 3757 3764 3771 3775 3835
 261► 3848 3853 3884 4111 4112 4119 4121 4136 4156 4163 4165 4179 4191 4197 4199 4211 4233 4249 4277 4294
 281► 4316 4323 4332 4361 4367 4376 4388 4429 4459 4466 4467 4476 4492 4495 4499 4516 4549 4552 4561 4594
 301► 4613 4615 4631 4637 4646 4647 4651 4664 4673 4674 4717 4719 4727 4736 4738 4746 4763 4764 4771 4772
 321► 4779 4783 4791 4797 4837 4838 4873 4883 4911 4915 4917 4919 4924 4942 4945 4949 4951 4954 4971 4977
 341► 4991 4994 4999 5111 5112 5113 5118 5119 5121 5131 5135 5137 5146 5148 5149 5153 5157 5158 5164 5173
 361► 5175 5177 5179 5181 5184 5185 5191 5194 5195 5197 5211 5228 5232 5245 5254 5255 5256 5265 5282 5299
 381► 5311 5315 5317 5322 5335 5338 5351 5353 5355 5371 5377 5383 5416 5418 5419 5425 5449 5452 5461 5481
 401► 5491 5494 5513 5517 5518 5519 5524 5525 5526 5531 5533 5535 5542 5547 5548 5552 5553 5557 5558 5562
 421► 5569 5571 5574 5575 5579 5581 5584 5585 5591 5596 5597 5614 5625 5641 5652 5659 5695 5711 5713 5715
 441► 5717 5719 5731 5737 5745 5751 5754 5755 5759 5771 5773 5777 5778 5787 5791 5795 5799 5811 5814 5815
 461► 5822 5827 5833 5841 5845 5851 5854 5855 5872 5877 5899 5911 5914 5915 5917 5929 5941 5944 5951 5956
 481► 5957 5965 5971 5975 5979 5989 5992 5997 5998 5999 6111 6117 6119 6134 6143 6145 6149 6154 6167 6168
 501► 6171 6176 6177 6178 6179 6186 6187 6191 6194 6197 6222 6255 6277 6314 6341 6347 6374 6413 6415 6419
 521► 6431 6437 6446 6447 6451 6464 6473 6474 6491 6514 6525 6541 6552 6559 6595 6616 6617 6618 6644 6661
 541► 6667 6671 6676 6677 6678 6681 6687 6699 6711 6716 6717 6718 6719 6727 6734 6743 6744 6759 6761 6766
 561► 6767 6768 6771 6772 6775 6776 6777 6778 6779 6781 6786 6787 6788 6791 6795 6797 6811 6816 6817 6861
 581► 6865 6867 6871 6876 6877 6878 6887 6911 6914 6917 6941 6955 6957 6969 6971 6975 6977 6996 6999 7111
 601► 7112 7115 7116 7117 7118 7119 7121 7122 7127 7135 7137 7147 7149 7151 7153 7155 7157 7159 7161 7166
 621► 7167 7168 7169 7171 7172 7173 7174 7175 7176 7177 7178 7181 7186 7187 7191 7194 7195 7196 7211 7212
 641► 7217 7221 7229 7247 7258 7267 7271 7274 7276 7277 7279 7285 7289 7292 7297 7298 7299 7315 7317 7346
 661► 7348 7351 7353 7357 7364 7371 7375 7381 7384 7417 7419 7425 7427 7436 7438 7446 7452 7455 7463 7464
 681► 7471 7472 7479 7483 7491 7497 7511 7513 7515 7517 7519 7524 7528 7531 7533 7537 7542 7545 7551 7554
 701► 7555 7559 7567 7569 7571 7573 7576 7577 7578 7582 7587 7591 7595 7596 7597 7599 7611 7616 7617 7618
 721► 7619 7627 7634 7643 7644 7657 7659 7661 7666 7667 7668 7671 7672 7675 7676 7677 7678 7679 7681 7686
 741► 7687 7688 7691 7695 7697 7711 7712 7713 7714 7715 7716 7717 7718 7721 7724 7726 7727 7729 7731 7735
 761► 7739 7741 7742 7744 7749 7751 7753 7756 7757 7758 7759 7761 7762 7765 7766 7767 7768 7769 7771 7772
 781► 7775 7776 7777 7778 7779 7781 7785 7786 7787 7788 7789 7792 7793 7794 7795 7796 7797 7798 7799 7811
 801► 7813 7816 7817 7825 7829 7831 7834 7843 7852 7857 7861 7866 7867 7868 7869 7871 7875 7876 7877 7878
 821► 7879 7886 7887 7888 7892 7896 7897 7899 7911 7913 7914 7915 7916 7922 7927 7928 7929 7931 7937 7941
 841► 7946 7947 7951 7955 7956 7957 7959 7961 7964 7965 7967 7968 7972 7973 7974 7975 7976 7977 7978 7979
 861► 7982 7986 7987 7989 7992 7994 7995 7997 7998 7999 8115 8116 8117 8119 8137 8145 8151 8154 8155 8161
 881► 8166 8167 8171 8173 8176 8177 8191 8199 8225 8249 8252 8257 8275 8279 8294 8297 8317 8335 8338 8347
 901► 8348 8353 8371 8374 8383 8384 8415 8429 8437 8438 8451 8455 8473 8483 8492 8511 8514 8515 8522 8525
 921► 8527 8533 8541 8545 8551 8552 8554 8555 8558 8566 8572 8577 8585 8599 8611 8616 8617 8656 8661 8665
 941► 8667 8671 8676 8677 8678 8679 8687 8697 8711 8713 8716 8717 8725 8729 8731 8734 8743 8752 8757 8761
 961► 8766 8767 8768 8769 8771 8775 8776 8777 8778 8779 8786 8787 8788 8792 8796 8797 8799 8811 8833 8834
 981► 8843 8855 8867 8876 8877 8878 8887 8888 8889 8898 8899 8911 8919 8924 8927 8942 8959 8967 8972 8976
1001► 8977 8979 8987 8988 8989 8991 8994 8995 8997 8998 8999 9111 9112 9114 9115 9116 9117 9118 9119 9121
1021► 9129 9137 9141 9145 9146 9147 9149 9151 9154 9155 9157 9161 9164 9167 9171 9173 9174 9175 9176 9181
1041► 9185 9189 9191 9192 9194 9198 9199 9211 9219 9227 9229 9238 9244 9248 9259 9272 9277 9278 9279 9283
1061► 9284 9287 9291 9292 9295 9297 9299 9317 9319 9328 9371 9377 9382 9391 9411 9415 9416 9417 9419 9424
1081► 9428 9442 9445 9449 9451 9454 9461 9467 9471 9476 9477 9479 9482 9489 9491 9494 9497 9498 9499 9511
1101► 9514 9515 9517 9518 9527 9529 9541 9544 9551 9556 9557 9559 9565 9567 9571 9572 9575 9576 9577 9579
1121► 9581 9589 9592 9595 9597 9598 9599 9611 9614 9617 9641 9647 9655 9657 9669 9671 9674 9675 9677 9678
1141► 9687 9696 9699 9711 9713 9714 9715 9716 9722 9725 9727 9728 9729 9731 9737 9741 9746 9747 9749 9751
1161► 9752 9755 9756 9757 9759 9761 9764 9765 9767 9768 9772 9773 9774 9775 9776 9777 9778 9779 9782 9786
1181► 9787 9788 9789 9792 9794 9795 9797 9798 9799 9811 9815 9819 9823 9824 9827 9832 9842 9849 9851 9858
1201► 9859 9867 9872 9876 9877 9878 9879 9885 9887 9888 9889 9891 9894 9895 9897 9898 9899 9911 9912 9913
1221► 9914 9918 9919 9921 9922 9925 9927 9929 9931 9941 9944 9945 9947 9948 9949 9952 9954 9955 9957 9958
1241► 9959 9966 9969 9972 9974 9975 9977 9978 9979 9981 9984 9985 9987 9988 9989 9991 9992 9994 9995 9996
1261► 9997 9998 9999

I'd be interested if anyone would verify that all the numbers above are unsolvable for the 24 game.     -- Gerard Schildberger (talk) 23:31, 3 January 2019 (UTC)

Edited: I accidentally listed the groups with only one solution as unsolvable. Fixed now.

Um. You may want to re-read the task rules, specifically the one stating "The order of the digits when given does not have to be preserved."

I don't need to re-read the task rules, I programmed the REXX program which does NOT preserve the order of digits when presenting solutions, but it does honor the original number being processed and shows (all) the solutions for that number, for any order of its digits.   The task's requirement said that it   does not not have to be preserved,   it didn't say   should not be preserved.   I choose to preserve the order of digits for the REXX entry.     -- Gerard Schildberger (talk) 00:27, 5 January 2019 (UTC)

That being the case, there are only 495 unique combinations of 4 non-zero digits. This is ALL of them.

   Unsolvable:
   1111 1112 1113 1114 1115 1116 1117 1119 1122 1123 1124 1125 1133 1159 1167 1177
   1178 1179 1189 1199 1222 1223 1299 1355 1499 1557 1558 1577 1667 1677 1678 1777
   1778 1899 1999 2222 2226 2279 2299 2334 2555 2556 2599 2677 2777 2779 2799 2999
   3358 3467 3488 3555 3577 4459 4466 4467 4499 4779 4999 5557 5558 5569 5579 5777
   5778 5799 5899 5999 6667 6677 6678 6699 6777 6778 6779 6788 6999 7777 7778 7779
   7788 7789 7799 7888 7899 7999 8888 8889 8899 8999 9999

   Solvable:
   1118 1126 1127 1128 1129 1134 1135 1136 1137 1138 1139 1144 1145 1146 1147 1148
   1149 1155 1156 1157 1158 1166 1168 1169 1188 1224 1225 1226 1227 1228 1229 1233
   1234 1235 1236 1237 1238 1239 1244 1245 1246 1247 1248 1249 1255 1256 1257 1258
   1259 1266 1267 1268 1269 1277 1278 1279 1288 1289 1333 1334 1335 1336 1337 1338
   1339 1344 1345 1346 1347 1348 1349 1356 1357 1358 1359 1366 1367 1368 1369 1377
   1378 1379 1388 1389 1399 1444 1445 1446 1447 1448 1449 1455 1456 1457 1458 1459
   1466 1467 1468 1469 1477 1478 1479 1488 1489 1555 1556 1559 1566 1567 1568 1569
   1578 1579 1588 1589 1599 1666 1668 1669 1679 1688 1689 1699 1779 1788 1789 1799
   1888 1889 2223 2224 2225 2227 2228 2229 2233 2234 2235 2236 2237 2238 2239 2244
   2245 2246 2247 2248 2249 2255 2256 2257 2258 2259 2266 2267 2268 2269 2277 2278
   2288 2289 2333 2335 2336 2337 2338 2339 2344 2345 2346 2347 2348 2349 2355 2356
   2357 2358 2359 2366 2367 2368 2369 2377 2378 2379 2388 2389 2399 2444 2445 2446
   2447 2448 2449 2455 2456 2457 2458 2459 2466 2467 2468 2469 2477 2478 2479 2488
   2489 2499 2557 2558 2559 2566 2567 2568 2569 2577 2578 2579 2588 2589 2666 2667
   2668 2669 2678 2679 2688 2689 2699 2778 2788 2789 2888 2889 2899 3333 3334 3335
   3336 3337 3338 3339 3344 3345 3346 3347 3348 3349 3355 3356 3357 3359 3366 3367
   3368 3369 3377 3378 3379 3388 3389 3399 3444 3445 3446 3447 3448 3449 3455 3456
   3457 3458 3459 3466 3468 3469 3477 3478 3479 3489 3499 3556 3557 3558 3559 3566
   3567 3568 3569 3578 3579 3588 3589 3599 3666 3667 3668 3669 3677 3678 3679 3688
   3689 3699 3777 3778 3779 3788 3789 3799 3888 3889 3899 3999 4444 4445 4446 4447
   4448 4449 4455 4456 4457 4458 4468 4469 4477 4478 4479 4488 4489 4555 4556 4557
   4558 4559 4566 4567 4568 4569 4577 4578 4579 4588 4589 4599 4666 4667 4668 4669
   4677 4678 4679 4688 4689 4699 4777 4778 4788 4789 4799 4888 4889 4899 5555 5556
   5559 5566 5567 5568 5577 5578 5588 5589 5599 5666 5667 5668 5669 5677 5678 5679
   5688 5689 5699 5779 5788 5789 5888 5889 6666 6668 6669 6679 6688 6689 6789 6799
   6888 6889 6899 7889

   Solvable but only one solution:
   1277 1346 1668 3355 3388 5555 5588 5599

But even putting that aside, with a quick peek at your "unsolvable" list, I pick out 1164 (1*1*6*4), 1183 (1*1*8*3), 2232 (2*2*3*2) and many other that don't require digit reordering. I think you need to revisit your filtering algorithm. --Thundergnat (talk) 02:22, 4 January 2019 (UTC)

It wasn't the filtering that caused the error, but my post-editing process.   The REXX program did, in fact, find solutions for   1164   (and it's variants).     -- Gerard Schildberger (talk) 00:27, 5 January 2019 (UTC)