Added various fixes

csp_solver.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 
 from sudoku import Game
+from copy import deepcopy
 
 MAX_V = 9
 class State:
@@ -15,17 +16,16 @@ class State:
         self.resultboard = resultboard
 
         choicesboard = []
-        # Populate the numbers vector with values from 1 to MAX_V
-
-        # choicesboard is a bidimensional list with numbers for every element
+        numbers = set()
+        for value in range(1,10):
+            numbers.add(value)
         for x in range(MAX_V):
             row = []
             for y in range(MAX_V):
-                numbers = set()
-                for value in range(1,10):
-                    numbers.add(value)
-                row.append(numbers)
-            choicesboard.append(row)
+                choices = deepcopy(numbers)
+                row.append(choices)
+            newrow=deepcopy(row)
+            choicesboard.append(newrow)
         self.choicesboard = choicesboard
 
 def actions(state):
@@ -41,7 +41,9 @@ def actions(state):
     return actions
 
 def result(state,move):
-    state.resultboard[move['col']][move['row']] = move['num']
+    newState = deepcopy(state)
+    newState.resultboard[move['col']][move['row']] = move['num']
+    return newState
 
 def goalTest(state):
     incomplete = False
@@ -52,24 +54,26 @@ def goalTest(state):
     return incomplete
 
 def eliminateIllValues(state):
+    newState = deepcopy(state)
     for row in range(MAX_V):
         for col in range(MAX_V):
-            if state.resultboard[col][row] != 0:
-                num = state.resultboard[col][row]
+            if newState.resultboard[col][row] != 0:
+                num = newState.resultboard[col][row]
                 # Eliminate duplicates numbers in a row
                 for x in range(MAX_V):
-                    state.choicesboard[x][row].remove(num)
+                    newState.choicesboard[x][row].remove(num)
                     # Eliminate duplicates numbers in a column
                 for y in range(MAX_V):
-                    state.choicesboard[col][y].remove(num)
+                    newState.choicesboard[col][y].remove(num)
                     # Eliminate duplicates in block (working only for 9x9 cells)
                 #for y in range(MAX_V)
                 #    choicesboard[col][y].del(state.resultboard[col][row])
+    return newState
 
 if __name__ == "__main__":
     node = State()
     while not goalTest(node):
-        move=actions(node).pop()
-        result(node,move)
-        eliminateIllValues(node)
+        move = actions(node).pop()
+        node = result(node,move)
+        node = eliminateIllValues(node)
     print('Result found!')