Add a finiteness test

README.md

@@ -53,4 +53,12 @@ Nessler 2022:
 Starting hands: ---AJ--Q---------QAKQJJ-QK/-----A----KJ-K--------A---
 There were 8344 turns
 There were 1164 tricks
-````
+````
+
+There are [alternate versions of the game](https://github.com/matthewmayer/beggarmypython/pull/5) that do not terminate, entering an infinite loop. For example the Italian game of Camicia uses a 40-card deck and no draw-4 cards (aces).
+
+```
+Carmicia
+Starting hands: --Q------QJ----JK---/---Q---J-Q-KJ--K-K--
+Game appears to be infinite, loop detected after 197 turns and 37 tricks
+```

beggarmypython/__init__.py

@@ -3,6 +3,14 @@ def penalty_value_of(card):
     return values[card]
 
 def play(hands,firstCardOnLeft=True,verbose=False):
+    (turns, tricks, finite) = calculate(hands,firstCardOnLeft,verbose)
+    if finite:
+        print("There were %d turns" % turns)
+        print("There were %d tricks\n" % tricks)
+    else:
+        print("Game appears to be infinite, loop detected after %d turns and %d tricks" % (turns, tricks))
+
+def calculate(hands,firstCardOnLeft=True,verbose=False):
     a,b = hands #hands are called a and b
     print("Starting hands: %s/%s" % (a, b))
     if not firstCardOnLeft:
@@ -12,7 +20,9 @@ def play(hands,firstCardOnLeft=True,verbose=False):
     turns = 0
     tricks = 0
     player = 1 #alternates between 1 and -1
-    while a!="" and b!="": #game terminates when a or b's hands are empty
+    finite = True
+    visited = set() #keep the visited statuses
+    while a!="" and b!="" and finite: #game terminates when a or b's hands are empty
         battle_in_progress = False
         cards_to_play = 1
         while cards_to_play>0: #current player may play up to cards_to_play cards
@@ -58,8 +68,13 @@ def play(hands,firstCardOnLeft=True,verbose=False):
         player = player*-1
 
         #print current status
+        status = "%s/%s/%s" % (a, b, stack)
         if verbose:
-            print("%s/%s/%s" % (a, b, stack))
-
-    print("There were %d turns" % turns)
-    print("There were %d tricks\n" % tricks)
+            print(status)
+
+        #check for finiteness
+        if status in visited:
+            finite = False
+        else:
+            visited.add(status)
+    return (turns, tricks, finite)

test.py

@@ -27,3 +27,6 @@
 
 print("Nessler 2022:")
 beggarmypython.play(('---AJ--Q---------QAKQJJ-QK','-----A----KJ-K--------A---'), verbose=False)
+
+print("Carmicia")
+beggarmypython.play(('--Q------QJ----JK---','---Q---J-Q-KJ--K-K--'))