From 9fbc6297f917272a38b673fea4a732d73ff54bf9 Mon Sep 17 00:00:00 2001
From: wi11-holdsworth <83637728+wi11-holdsworth@users.noreply.github.com>
Date: Tue, 26 Aug 2025 21:33:16 +1000
Subject: [PATCH] fix bug with unify_diagonal

---
 main.pl | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/main.pl b/main.pl
index 9d908fd..dd6a468 100644
--- a/main.pl
+++ b/main.pl
@@ -9,7 +9,7 @@
 %
 puzzle_solution(Puzzle) :-
   Puzzle = [_|Rows],
-  % unify_diagonal(Puzzle),
+  unify_diagonal(Puzzle),
   maplist(valid_row, Rows),
   transpose(Puzzle, TransposedPuzzle),
   TransposedPuzzle = [_|Columns],
@@ -60,7 +60,8 @@ main_diagonal([M|Ms], I, [D|Ds]) :-
 all_same([Head|Tail]) :-
   all_same(Head, Tail).
 
+all_same(X, [X]).
 all_same(Head, [X|Xs]) :-
-  Head = X,
+  Head #= X,
   all_same(Head, Xs).