Twelve statements

Twelve statements is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

This puzzle is borrowed from here.

Given the following twelve statements, which of them are true?

1.  This is a numbered list of twelve statements.
2.  Exactly 3 of the last 6 statements are true.
3.  Exactly 2 of the even-numbered statements are true.
4.  If statement 5 is true, then statements 6 and 7 are both true.
5.  The 3 preceding statements are all false.
6.  Exactly 4 of the odd-numbered statements are true.
7.  Either statement 2 or 3 is true, but not both.
8.  If statement 7 is true, then 5 and 6 are both true.
9.  Exactly 3 of the first 6 statements are true.
10.  The next two statements are both true.
11.  Exactly 1 of statements 7, 8 and 9 are true.
12.  Exactly 4 of the preceding statements are true.

When you get tired of trying to figure it out in your head, write a program to solve it, and print the correct answer or answers.

Extra credit: also print out a table of near misses, that is, solutions that are contradicted by only a single statement.

Haskell

<lang haskell>tf [x] = [[True], [False]] tf (x:xs) = map (True:) s ++ map (False:) s where s = tf xs

sumbool = sum . map fromEnum wrongness b = sumbool . zipWith (/=) b . map (\f -> f b)

statements = [ (==12) . length, sumto 3 [len - 6..], sumto 2 [1,3..], \b -> not (b!!4) || all (b!!) [5,6], \b -> not $ any (b!!) [2..4], sumto 4 [0,2..], sumto 1 [1,2], \b -> not (b!!6) || all (b!!) [4,5], sumto 3 [0..5], sumto 2 [10,11], sumto 1 [6,7,8], sumto 4 [0..10] ] where len = length statements sumto s x b = s == (sumbool . map (b!!) . takeWhile (< length b)) x

main = let t n s = filter ((==n).fst) [(wrongness b s, b) | b <- tf s] in do putStrLn "Answer" mapM_ print $ t 0 statements putStrLn "Near misses" mapM_ print $ t 1 statements</lang>

Output:

Answer
(0,[True,False,True,True,False,True,True,False,False,False,True,False])
Near misses
(1,[True,True,False,True,False,False,True,True,True,False,False,False])
(1,[True,True,False,True,False,False,True,False,True,True,False,False])
(1,[True,True,False,True,False,False,True,False,True,False,False,True])
(1,[True,False,True,True,False,True,True,False,True,False,False,False])
(1,[True,False,True,True,False,False,False,True,True,False,False,False])
(1,[True,False,False,True,False,True,False,True,True,False,False,False])
(1,[True,False,False,True,False,False,False,True,False,True,True,True])
(1,[True,False,False,True,False,False,False,False,False,False,False,False])
(1,[False,False,False,True,False,False,False,True,False,True,True,True])

Perl 6

<lang perl6>sub infix:<→> ($protasis,$apodosis) { !$protasis or $apodosis }

my @tests = { True }, # (there's no 0th statement)

   { all(.[1..12]) === any(True, False) },
   { 3 == [+] .[7..12] },
   { 2 == [+] .[2,4...12] },
   { .[5] → all .[6,7] },
   { none .[2,3,4] },
   { 4 == [+] .[1,3...11] },
   { one .[2,3] },
   { .[7] → all .[5,6] },
   { 3 == [+] .[1..6] },
   { all .[11,12] },
   { one .[7,8,9] },
   { 4 == [+] .[1..11] };

my @good; my @bad; my @ugly;

for reverse 0 ..^ 2**12 -> $i {

   my @b = $i.fmt("%012b").comb;
   my @assert = True, @b.map: { .so }
   my @result = @tests.map: { .(@assert).so }
   my @s = ( $_ if $_ and @assert[$_] for 1..12 );
   if @result eqv @assert {

push @good, "<{@s}> is consistent.";

   }
   else {

my @cons = gather for 1..12 { if @assert[$_] !eqv @result[$_] { take @result[$_] ?? $_ !! "¬$_"; } } my $mess = "<{@s}> implies {@cons}."; if @cons == 1 { push @bad, $mess } else { push @ugly, $mess }

   }

}

.say for @good; say "\nNear misses:"; .say for @bad;</lang>

Output:

<1 3 4 6 7 11> is consistent.

Near misses:
<1 2 4 7 8 9> implies ¬8.
<1 2 4 7 9 10> implies ¬10.
<1 2 4 7 9 12> implies ¬12.
<1 3 4 6 7 9> implies ¬9.
<1 3 4 8 9> implies 7.
<1 4 6 8 9> implies ¬6.
<1 4 8 10 11 12> implies ¬12.
<1 4> implies 8.
<1 5 6 9 11> implies 8.
<1 5 8 10 11 12> implies ¬12.
<1 5 8 11> implies 12.
<1 5 8> implies 11.
<1 5> implies 8.
<4 8 10 11 12> implies 1.
<5 8 10 11 12> implies 1.
<5 8 11> implies 1.