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feat: q3 & fix: update visited list in DFS, BFS

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snsd0805 2024-03-22 01:53:39 +08:00
parent 4d6660ab66
commit 69a328e196
Signed by: snsd0805
GPG Key ID: 569349933C77A854
1 changed files with 37 additions and 4 deletions
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41
search.py
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@ -88,7 +88,7 @@ def depthFirstSearch(problem: SearchProblem):
curr_state = problem.getStartState() curr_state = problem.getStartState()
isGoal = problem.isGoalState(curr_state) isGoal = problem.isGoalState(curr_state)
visited = set() visited = set([curr_state])
stack = util.Stack() stack = util.Stack()
while not isGoal: while not isGoal:
@ -96,7 +96,6 @@ def depthFirstSearch(problem: SearchProblem):
successors = problem.getSuccessors(curr_state) successors = problem.getSuccessors(curr_state)
for (state, direction, cost) in successors: for (state, direction, cost) in successors:
if state not in visited: if state not in visited:
visited.add(state)
stack.push({ stack.push({
'state': (state, direction, cost), 'state': (state, direction, cost),
'actions': actions 'actions': actions
@ -108,6 +107,7 @@ def depthFirstSearch(problem: SearchProblem):
else: else:
obj = stack.pop() obj = stack.pop()
(curr_state, direction, cost) = obj['state'] (curr_state, direction, cost) = obj['state']
visited.add(curr_state)
actions = obj['actions'] + [ direction ] actions = obj['actions'] + [ direction ]
isGoal = problem.isGoalState(curr_state) isGoal = problem.isGoalState(curr_state)
@ -123,7 +123,7 @@ def breadthFirstSearch(problem: SearchProblem):
curr_state = problem.getStartState() curr_state = problem.getStartState()
isGoal = problem.isGoalState(curr_state) isGoal = problem.isGoalState(curr_state)
visited = set() visited = set([curr_state])
queue = util.Queue() queue = util.Queue()
while not isGoal: while not isGoal:
@ -152,7 +152,40 @@ def breadthFirstSearch(problem: SearchProblem):
def uniformCostSearch(problem: SearchProblem): def uniformCostSearch(problem: SearchProblem):
"""Search the node of least total cost first.""" """Search the node of least total cost first."""
"*** YOUR CODE HERE ***" "*** YOUR CODE HERE ***"
util.raiseNotDefined() actions = []
curr_state = problem.getStartState()
isGoal = problem.isGoalState(curr_state)
costs = 0
visited = set([curr_state])
queue = util.PriorityQueue()
while not isGoal:
# push in the P Queue
successors = problem.getSuccessors(curr_state)
for (state, direction, cost) in successors:
if state not in visited:
queue.push({
'state': (state, direction, cost),
'actions': actions,
'costs': costs
}, costs + cost) # if visited this successor node, how much cost will the agent need
# check whether reachable
if queue.isEmpty():
return []
else:
obj = queue.pop()
(curr_state, direction, cost) = obj['state']
visited.add(curr_state)
actions = obj['actions'] + [ direction ]
costs = obj['costs'] + cost
isGoal = problem.isGoalState(curr_state)
return actions
def nullHeuristic(state, problem=None): def nullHeuristic(state, problem=None):
""" """