import heapqclass Cell(object):def __init__(self, x, y, reachable):self.reachable = reachableself.x = xself.y = yself.parent = Noneself.g = 0self.h = 0self.f = 0class AStar(object):def __init__(self):self.op = []heapq.heapify(self.op)self.cl = set()self.cells = []self.gridHeight = 6self.gridWidth = 6def init_grid(self):walls = ((0, 5), (1, 0), (1, 1), (1, 5), (2, 3),(3, 1), (3, 2), (3, 5), (4, 1), (4, 4), (5, 1))for x in range(self.gridWidth):for y in range(self.gridHeight):if (x, y) in walls:reachable = Falseelse:reachable = Trueself.cells.append(Cell(x, y, reachable))self.start = self.get_cell(0, 0)self.end = self.get_cell(5, 5)def get_heuristic(self, cell):return 10 * (abs(cell.x - self.end.x) + abs(cell.y - self.end.y))def get_cell(self, x, y):return self.cells[x * self.gridHeight + y]def get_adjacent_cells(self, cell):cells = []if cell.x < self.gridWidth-1:cells.append(self.get_cell(cell.x+1, cell.y))if cell.y > 0:cells.append(self.get_cell(cell.x, cell.y-1))if cell.x > 0:cells.append(self.get_cell(cell.x-1, cell.y))if cell.y < self.gridHeight-1:cells.append(self.get_cell(cell.x, cell.y+1))return cellsdef display_path(self):cell = self.endwhile cell.parent is not self.start:cell = cell.parentprint 'path: cell: %d,%d' % (cell.x, cell.y)def update_cell(self, adj, cell):adj.g = cell.g + 10adj.h = self.get_heuristic(adj)adj.parent = celladj.f = adj.h + adj.gdef process(self):heapq.heappush(self.op, (self.start.f, self.start))while len(self.op):f, cell = heapq.heappop(self.op)self.cl.add(cell)if cell is self.end:self.display_path()breakadj_cells = self.get_adjacent_cells(cell)for c in adj_cells:if c.reachable:if c in self.cl:if (c.f, c) in self.op:if c.g > cell.g + 10:self.update_cell(c, cell)else:self.update_cell(c, cell)heapq.heappush(self.op, (c.f, c))if __name__ == "__main__":a = AStar()a.init_grid()a.process()