port of PYSWIP package.

packages/pyswip/examples/draughts/puzzle1.py

@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+
+# This example is adapted from http://eclipse.crosscoreop.com/examples/puzzle1.pl.txt
+
+# "Twelve draught pieces are arranged in a square frame with four on
+# each side.  Try placing them so there are 5 on each side.  (Kordemsky)
+#
+# "Maybe this problem is not described very well but I wanted to stick
+# with the original text from Kordemsky.  The problem may be stated in
+# terms of guards on the wall of a square fort.  If a guard stands on a
+# side wall then he may only watch that particular wall whereas a guard
+# at a corner may watch two walls.  If twelve guards are positioned such
+# that there are two on each side wall and one at each corner then there
+# are four guards watching each wall.  How can they be rearranged such
+# that there are five watching each wall?"
+
+from pyswip.prolog import Prolog
+
+def main():
+    prolog = Prolog()
+    prolog.consult("puzzle1.pl")
+    for soln in prolog.query("solve(B)."):
+        #B = eval(soln["B"])
+        B = soln["B"]
+        # [NW,N,NE,W,E,SW,S,SE]
+        print "%d %d %d" % tuple(B[:3])
+        print "%d   %d"   % tuple(B[3:5])
+        print "%d %d %d" % tuple(B[5:])
+        
+        cont = raw_input("Press 'n' to finish: ")
+        if cont.lower() == "n": break
+        
+if __name__ == "__main__":
+    main()