45 lines
1.5 KiB
Python
45 lines
1.5 KiB
Python
import heapq
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import itertools
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from strategies.pathfinding_strategy import PathFindingStrategy
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class AStarStrategy(PathFindingStrategy):
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def heuristic(self, cell, exit_cell):
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return abs(cell.x - exit_cell.x) + abs(cell.y - exit_cell.y)
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def find_path(self, maze, start_cell, exit_cell):
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open_set = []
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counter = itertools.count()
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heapq.heappush(open_set, (0, next(counter), start_cell))
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parents = {start_cell: None}
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g_score = {start_cell: 0}
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visited = set()
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visited_count = 0
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while open_set:
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_, _, current = heapq.heappop(open_set)
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if current in visited:
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continue
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visited.add(current)
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visited_count += 1
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if current == exit_cell:
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path = []
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while current is not None:
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path.append(current)
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current = parents[current]
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path.reverse()
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return path, visited_count
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for neighbor in maze.get_neighbors(current):
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tentative_g = g_score[current] + 1
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if neighbor not in g_score or tentative_g < g_score[neighbor]:
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parents[neighbor] = current
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g_score[neighbor] = tentative_g
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f_score = tentative_g + self.heuristic(neighbor, exit_cell)
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heapq.heappush(open_set, (f_score, next(counter), neighbor))
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return [], visited_count |