Data commit

Task/Long-year/Prolog/long-year.pro

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+% See https://en.wikipedia.org/wiki/ISO_week_date#Weeks_per_year
+
+p(Year, P):-
+    P is (Year + (Year//4) - (Year//100) + (Year//400)) mod 7.
+
+long_year(Year):-
+    p(Year, 4),
+    !.
+long_year(Year):-
+    Year_before is Year - 1,
+    p(Year_before, 3).
+
+print_long_years(From, To):-
+    writef("Long years between %w and %w:\n", [From, To]),
+    print_long_years(From, To, 0),
+    nl.
+
+print_long_years(From, To, _):-
+    From > To,
+    !.
+print_long_years(From, To, Count):-
+    long_year(From),
+    !,
+    (Count > 0 ->
+        (0 is Count mod 10 -> nl ; write(' '))
+        ;
+        true
+    ),
+    write(From),
+    Count1 is Count + 1,
+    Next is From + 1,
+    print_long_years(Next, To, Count1).
+print_long_years(From, To, Count):-
+    Next is From + 1,
+    print_long_years(Next, To, Count).
+
+main:-
+     print_long_years(1800, 2100).