adds zebrapuzzles

reasoning_gym/logic/contrib/logic_puzzle/graph/solver_utils.py

@@ -0,0 +1,34 @@
+from z3 import *
+
+
+def column(matrix, i):
+    return [matrix[j][i] for j in range(len(matrix))]
+
+def instanciate_int_constrained(name, s, card):
+    x = Int(name)
+    # Each int represent an index in p[name]
+    s.add(x >= 0, x <= card - 1)
+    return x
+
+def count_solutions(s, max=1e9):
+    count = 0
+    while s.check() == sat:
+        count += 1
+        if count >= max:
+            return count
+        m = s.model()
+
+        # Create a new constraint the blocks the current model
+        block = []
+        for d in m:
+            # d is a declaration
+            if d.arity() > 0:
+                raise Z3Exception("uninterpreted functions are not supported")
+            # create a constant from declaration
+            c = d()
+            if is_array(c) or c.sort().kind() == Z3_UNINTERPRETED_SORT:
+                raise Z3Exception("arrays and uninterpreted sorts are not supported")
+            block.append(c != m[d])
+
+        s.add(Or(block))
+    return count