系統操作說明

    {
      ""pros"": [
        ""relaxing atmosphere"",
        ""attentive and efficient staff"",
        ""high-quality services""
      ],
      ""cons"": [
        ""pricey"",
        ""no cell phone policy"",
        ""no refreshments""
      ]
    }
    

    import heapq

    class Node:
        """"""
        Represents a node in the grid for A* pathfinding.

        Attributes:
            x (int): The x-coordinate of the node.
            y (int): The y-coordinate of the node.
            parent (Node, optional): The parent node in the path. Defaults to None.
            g (int): Cost from the start node to this node. Defaults to 0.
            h (int): Estimated cost from this node to the end node. Defaults to 0.
        """"""

        def __init__(self, x, y, parent=None):
            self.x = x
            self.y = y
            self.parent = parent
            self.g = 0
            self.h = 0

        def __lt__(self, other):
            """"""Compares nodes based on their f-score (g + h).""""""
            return (self.g + self.h) < (other.g + other.h)

    def a_star(grid, start, end):
        """"""
        Implements the A* pathfinding algorithm.

        Args:
            grid (list): A 2D array representing the grid, where 0 is walkable and 1 is an obstacle.
            start (tuple): The starting point coordinates (x, y).
            end (tuple): The end point coordinates (x, y).

        Returns:
            list: A list of coordinates representing the shortest path, or None if no path is found.
        """"""

        rows = len(grid)
        cols = len(grid[0])

        # Create start and end nodes
        start_node = Node(start[0], start[1])
        end_node = Node(end[0], end[1])

        # Initialize open and closed lists
        open_list = []
        closed_list = set()

        # Add the start node to the open list
        heapq.heappush(open_list, start_node)

        while open_list:
            # Get the node with the lowest f-score
            current_node = heapq.heappop(open_list)

            # Add the current node to the closed list
            closed_list.add((current_node.x, current_node.y))

            # Check if we've reached the goal
            if current_node.x == end_node.x and current_node.y == end_node.y:
                # Reconstruct and return the path
                path = []
                while current_node:
                    path.append((current_node.x, current_node.y))
                    current_node = current_node.parent
                return path[::-1]  # Return reversed path

            # Explore neighboring nodes
            for dx, dy in [(0, -1), (0, 1), (-1, 0), (1, 0)]:  # Up, Down, Left, Right
                neighbor_x = current_node.x + dx
                neighbor_y = current_node.y + dy

                # Check if the neighbor is within the grid bounds
                if 0 <= neighbor_x < cols and 0 <= neighbor_y < rows:
                    # Check if the neighbor is walkable and not in the closed list
                    if grid[neighbor_y][neighbor_x] == 0 and (neighbor_x, neighbor_y) not in closed_list:
                        # Create a neighbor node
                        neighbor_node = Node(neighbor_x, neighbor_y, parent=current_node)

                        # Calculate the cost to reach the neighbor
                        neighbor_node.g = current_node.g + 1

                        # Calculate the heuristic (Manhattan distance)
                        neighbor_node.h = abs(neighbor_node.x - end_node.x) + abs(neighbor_node.y - end_node.y)

                        # Add the neighbor to the open list if it's a better path
                        if neighbor_node not in open_list:
                            heapq.heappush(open_list, neighbor_node)

        # No path found
        return None

    # Example usage:
    grid = [
        [0, 0, 0, 0, 0],
        [0, 1, 0, 1, 0],
        [0, 0, 0, 0, 0],
        [0, 1, 1, 1, 0],
        [0, 0, 0, 0, 0]
    ]

    start = (0, 0)
    end = (4, 4)

    path = a_star(grid, start, end)

    if path:
        print(""Shortest path:"", path)
    else:
        print(""No path found."")
    

    import heapq

    class Node:
        def __init__(self, position, parent=None):
            self.position = position
            self.parent = parent
            self.g = 0
            self.h = 0
            self.f = 0

        def __lt__(self, other):
            return self.f < other.f

    def astar(grid, start, end):
        rows = len(grid)
        cols = len(grid[0])

        open_list = []
        closed_list = set()

        start_node = Node(start)
        end_node = Node(end)

        open_list.append(start_node)

        while open_list:
            current_node = heapq.heappop(open_list)

            if current_node.position == end_node.position:
                path = []
                while current_node:
                    path.append(current_node.position)
                    current_node = current_node.parent
                return path[::-1]

            closed_list.add(current_node.position)

            for neighbor in get_neighbors(grid, current_node):
                if neighbor.position in closed_list:
                    continue

                if neighbor not in open_list:
                    neighbor.g = current_node.g + 1
                    neighbor.h = manhattan_distance(neighbor.position, end_node.position)
                    neighbor.f = neighbor.g + neighbor.h
                    neighbor.parent = current_node
                    heapq.heappush(open_list, neighbor)
                else:
                    if neighbor.g > current_node.g + 1:
                        neighbor.g = current_node.g + 1
                        neighbor.f = neighbor.g + neighbor.h
                        neighbor.parent = current_node
                        heapq.heapify(open_list)

        return None  # No path found

    def get_neighbors(grid, node):
        rows = len(grid)
        cols = len(grid[0])
        row, col = node.position
        neighbors = []
        if row > 0 and grid[row - 1][col] == 0:
            neighbors.append(Node((row - 1, col)))
        if row < rows - 1 and grid[row + 1][col] == 0:
            neighbors.append(Node((row + 1, col)))
        if col > 0 and grid[row][col - 1] == 0:
            neighbors.append(Node((row, col - 1)))
        if col < cols - 1 and grid[row][col + 1] == 0:
            neighbors.append(Node((row, col + 1)))
        return neighbors

    def manhattan_distance(a, b):
        return abs(a[0] - b[0]) + abs(a[1] - b[1])

    # Example usage
    grid = [
        [0, 0, 0, 0, 0],
        [0, 1, 1, 1, 0],
        [0, 0, 0, 0, 0],
        [0, 1, 1, 1, 0],
        [0, 0, 0, 0, 0],
    ]

    start = (0, 0)
    end = (4, 4)

    path = astar(grid, start, end)
    print(path)