88 lines
2.8 KiB
Python
88 lines
2.8 KiB
Python
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from abc import ABC, abstractmethod
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from collections import deque
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import heapq
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class PathFindingStrategy(ABC):
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@abstractmethod
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def findPath(self, maze, start, exit_cell):
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pass
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def restorePath(self, parent, start, exit_cell):
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path = []
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current = exit_cell
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while current != start:
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path.append(current)
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current = parent[current]
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path.append(start)
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path.reverse()
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return path
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class BFSStrategy(PathFindingStrategy):
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def findPath(self, maze, start, exit_cell):
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queue = deque([start])
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visited = {start}
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parent = {}
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while queue:
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current = queue.popleft()
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if current == exit_cell:
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return self.restorePath(parent, start, exit_cell), len(visited)
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for neighbor in maze.getNeighbors(current):
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if neighbor not in visited:
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visited.add(neighbor)
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parent[neighbor] = current
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queue.append(neighbor)
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return [], len(visited)
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class DFSStrategy(PathFindingStrategy):
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def findPath(self, maze, start, exit_cell):
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stack = [start]
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visited = {start}
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parent = {}
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while stack:
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current = stack.pop()
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if current == exit_cell:
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return self.restorePath(parent, start, exit_cell), len(visited)
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for neighbor in maze.getNeighbors(current):
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if neighbor not in visited:
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visited.add(neighbor)
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parent[neighbor] = current
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stack.append(neighbor)
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return [], len(visited)
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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 findPath(self, maze, start, exit_cell):
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pq = []
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heapq.heappush(pq, (0, id(start), start))
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parent = {}
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g_score = {start: 0}
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visited = set()
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while pq:
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_, _, current = heapq.heappop(pq)
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if current in visited:
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continue
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visited.add(current)
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if current == exit_cell:
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return self.restorePath(parent, start, exit_cell), len(visited)
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for neighbor in maze.getNeighbors(current):
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new_cost = g_score[current] + 1
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if neighbor not in g_score or new_cost < g_score[neighbor]:
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g_score[neighbor] = new_cost
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parent[neighbor] = current
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priority = new_cost + self.heuristic(neighbor, exit_cell)
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heapq.heappush(pq, (priority, id(neighbor), neighbor))
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return [], len(visited)
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