Merge pull request #10415 from 2colours/branch-for-challenge-277

Prolog solutions by 2colours

2 files changed, 31 insertions, 0 deletions

diff --git a/challenge-277/2colours/prolog/ch-1.p b/challenge-277/2colours/prolog/ch-1.p
new file mode 100644
index 0000000000..e02e5b8728
--- /dev/null
+++ b/challenge-277/2colours/prolog/ch-1.p
@@ -0,0 +1,17 @@
+build_uniq_assoc(Value, Assoc_Before, Assoc_After) :- 
+        put_assoc(Value, Assoc_Before, Valid_After, Assoc_After),
+        (get_assoc(Value, Assoc_Before, _Valid_Before) ->
+                Valid_After = false ;
+                Valid_After = true).
+
+task1(Words1, Words2, Nr_Common_Once) :-
+        empty_assoc(E),
+        maplist([Words, Result_Assoc]>>foldl(build_uniq_assoc, Words, E, Result_Assoc), [Words1, Words2], [Unique_Assoc1, Unique_Assoc2]),
+        findall([Word], (
+                gen_assoc(Word, Unique_Assoc1, Valid1),
+                get_assoc(Word, Unique_Assoc2, Valid2),
+                Valid1 == true,
+                Valid2 == true
+                ),
+                Good_Words),
+        length(Good_Words, Nr_Common_Once).
diff --git a/challenge-277/2colours/prolog/ch-2.p b/challenge-277/2colours/prolog/ch-2.p
new file mode 100644
index 0000000000..8c8a36b220
--- /dev/null
+++ b/challenge-277/2colours/prolog/ch-2.p
@@ -0,0 +1,14 @@
+:- use_module(library(clpfd)).
+
+find_value2(List, Index, Value, Value2) :-
+        Index2 #> Index,
+        nth0(Index2, List, Value2),
+        (Value2 - Value >= Value, !, fail ; true).
+
+task2(Ints, Nr_Strong_Pairs) :-
+        sort(Ints, Ints_Sorted),
+        findall([Value, Value2],
+                (nth0(Index, Ints_Sorted, Value),
+                find_value2(Ints_Sorted, Index, Value, Value2)),
+                Solutions),
+        length(Solutions, Nr_Strong_Pairs).