100 lines
3.3 KiB
Python
100 lines
3.3 KiB
Python
from queue import PriorityQueue
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DEFAULT_COST_VALUE = 1
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def is_border(x, y, max_x, max_y):
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return 0 <= x < max_x and 0 <= y < max_y
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def is_obstacle(x, y, obstacles):
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return (x, y) in obstacles
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def succ(current_state, max_x, max_y, obstacles):
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successors = []
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x, y, direction = current_state
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# Akcja: Do przodu
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direction_x, direction_y = {'N': (0, -1), 'E': (1, 0), 'S': (0, 1), 'W': (-1, 0)}[direction] # Słownik przesunięć w zależności od kierunku
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new_x, new_y = x + direction_x, y + direction_y
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if is_border(new_x, new_y, max_x, max_y) and not(is_obstacle(new_x, new_y, obstacles)):
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successors.append(((new_x, new_y, direction), 'Go Forward'))
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# Akcja: Obrót w lewo
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left_turns = {'N': 'W', 'W': 'S', 'S': 'E', 'E': 'N'} # Słownik kierunków po obrocie w lewo
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successors.append(((x, y, left_turns[direction]), 'Turn Left'))
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# Akcja: Obrót w prawo
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right_turns = {'N': 'E', 'E': 'S', 'S': 'W', 'W': 'N'} # Słownik kierunków po obrocie w prawo
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successors.append(((x, y, right_turns[direction]), 'Turn Right'))
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return successors
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def graphsearch(istate, goal, max_x, max_y, obstacles, cost_map):
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fringe = PriorityQueue()
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explored = set()
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fringe.put((0, (istate, None , None)))
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while not fringe.empty():
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_, node = fringe.get()
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state, _, _ = node
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if goaltest(state, goal):
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return build_action_sequence(node)
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explored.add(state)
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successors = succ(state, max_x, max_y, obstacles)
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for new_state, action in successors:
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new_node = (new_state, node, action)
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p_new_state = current_cost(node, cost_map) + heuristic(state, goal)
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if not is_state_in_queue(new_state, fringe) and new_state not in explored:
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fringe.put((p_new_state, new_node))
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elif is_state_in_queue(new_state, fringe):
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for i, (p_existing_state, (existing_state, _, _)) in enumerate(fringe.queue):
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if existing_state == new_state and p_existing_state > p_new_state:
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fringe.queue[i] = (p_new_state, new_node)
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else:
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break
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return False
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def is_state_in_queue(state, queue):
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for _, (s, _, _) in queue.queue:
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if s == state:
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return True
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return False
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def build_action_sequence(node):
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actions = []
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while node[1] is not None: # Dopóki nie dojdziemy do korzenia
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_, parent, action = node
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actions.append(action)
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node = parent
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actions.reverse()
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return actions
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def goaltest(state, goal):
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x, y, _ = state
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goal_x, goal_y = goal
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return (x,y) == (goal_x, goal_y)
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def current_cost(node, cost_map):
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cost = 0
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while node[1] is not None: # Dopóki nie dojdziemy do korzenia
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_, parent, action = node
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# Dodaj koszt pola z mapy kosztów tylko jeśli akcja to "Forward"
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if action == 'Go Forward':
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state, _, _ = node
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cost += cost_map.get(state[:2], DEFAULT_COST_VALUE) # Pobiera koszt przejścia przez dane pole, a jeśli koszt nie jest zdefiniowany to bierze wartość domyślną
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node = parent # Przejdź do rodzica
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return cost
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def heuristic(state, goal):
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x, y, _ = state
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goal_x, goal_y = goal
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return abs(x - goal_x) + abs(y - goal_y) # Odległość Manhattana do celu |