Fix search algorithm and finish project.

p1_search/search.py

@@ -80,19 +80,23 @@ def genericSearch(problem, getNewCostAndPriority):
     fringe.push((startState, [], 0), 0)
     visited = {}
 
-    while not fringe.isEmpty():
+    while True:
+        if fringe.isEmpty():
+            raise Exception("No path found.")
+
         state, actions, cost = fringe.pop()
+
         if problem.isGoalState(state):
             return actions
+
+        if state in visited and cost >= visited[state]:
+            continue
         visited[state] = cost
+
         for successor, action, stepCost in problem.getSuccessors(state):
             newCost, priority = getNewCostAndPriority(cost, stepCost, successor)
-            if successor in visited and visited[successor] <= newCost:
-                continue
             newActions = list(actions) + [action]
             fringe.push((successor, newActions, newCost), priority)
-    print("No path found.")
-    raise Exception()
 
 
 def depthFirstSearch(problem):