From ebb4f029818832ffd5e8a8820377e398e7fa9d7e Mon Sep 17 00:00:00 2001
From: Renge <renge@renge.io>
Date: Thu, 22 Feb 2024 01:07:29 -0500
Subject: [PATCH] fix: XSB incompetible(between)

---
 A/queens.P | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/A/queens.P b/A/queens.P
index c2d6170..25be237 100644
--- a/A/queens.P
+++ b/A/queens.P
@@ -1,3 +1,10 @@
+between(I, J, K) :-
+    I =< J,
+    (   I = K
+    ;   I1 is I+1,
+        between(I1, J, K)
+    ).
+
 legal_queens(N, Row, []) :- N =:= Row - 1.
 legal_queens(N, Row1, [(Row1, Col1)|Queens]) :-
     Row1 < N + 1,