132 lines
3.7 KiB
Go
132 lines
3.7 KiB
Go
package parser
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import (
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"fmt"
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"maze-solver/io/reader"
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"maze-solver/maze"
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)
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func Parse(reader reader.Reader) (*maze.Maze, error) {
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nodesByCoord := make(map[maze.Coordinates]*maze.Node)
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ret := &maze.Maze{}
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raw_maze, err := reader.Read()
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if err != nil {
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return nil, err
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}
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y := 0
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// Parse first line to get entrance
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for x := 0; x < raw_maze.Width-1; x++ {
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if raw_maze.IsPath(x, y) {
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coords := maze.Coordinates{X: x, Y: y}
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node := maze.NewNode(coords)
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ret.Nodes = append(ret.Nodes, node)
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nodesByCoord[coords] = node
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break
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}
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}
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for y = 1; y < raw_maze.Height-1; y++ {
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for x := 1; x < raw_maze.Width-1; x++ {
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// Parse middle of the maze
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if isCoordEligibleForNode(x, y, raw_maze) {
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coords := maze.Coordinates{X: x, Y: y}
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node := maze.NewNode(coords)
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lookupNeighbourAbove(raw_maze, node, &nodesByCoord, ret)
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ret.Nodes = append(ret.Nodes, node)
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nodesByCoord[coords] = node
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if raw_maze.IsPath(x-1, y) && raw_maze.IsWall(x+1, y) ||
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raw_maze.IsPath(x, y-1) &&
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(raw_maze.IsPath(x-1, y) || raw_maze.IsPath(x+1, y)) {
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lookupNeighbourLeft(raw_maze, node, &nodesByCoord)
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}
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}
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}
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}
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// Parse last line to get exit
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for x := 0; x < raw_maze.Width-1; x++ {
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if raw_maze.IsPath(x, y) {
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coords := maze.Coordinates{X: x, Y: y}
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node := maze.NewNode(coords)
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lookupNeighbourAbove(raw_maze, node, &nodesByCoord, ret)
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ret.Nodes = append(ret.Nodes, node)
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break
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}
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}
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return ret, nil
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}
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func isCoordEligibleForNode(x int, y int, raw_maze *reader.RawMaze) bool {
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return raw_maze.IsPath(x, y) &&
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(raw_maze.IsWall(x-1, y) && raw_maze.IsPath(x+1, y) || // wall left, path right
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raw_maze.IsPath(x-1, y) && raw_maze.IsWall(x+1, y) || // path left, wall right
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raw_maze.IsPath(x, y-1) && (raw_maze.IsPath(x-1, y) || raw_maze.IsPath(x+1, y)) || // path above and not in vertical corridor
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raw_maze.IsWall(x-1, y) && raw_maze.IsWall(x+1, y) && raw_maze.IsPath(x, y-1) && raw_maze.IsWall(x, y+1)) // wall to left, below, above and path above
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}
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func lookupNeighbourAbove(raw_maze *reader.RawMaze, node *maze.Node, nodesByCoord *map[maze.Coordinates]*maze.Node, m *maze.Maze) {
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for y := node.Coords.Y - 1; y >= 0; y-- {
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neighbour, ok := (*nodesByCoord)[maze.Coordinates{X: node.Coords.X, Y: y}]
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if ok {
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node.Up = neighbour
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neighbour.Down = node
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break
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}
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if y > 0 && raw_maze.IsWall(node.Coords.X, y) {
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y++
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if y == node.Coords.Y {
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break
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}
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coords := maze.Coordinates{X: node.Coords.X, Y: y}
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new_node := maze.NewNode(coords)
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lookupNeighbourLeft(raw_maze, new_node, nodesByCoord)
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lookupNeighbourRight(raw_maze, new_node, nodesByCoord)
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(*nodesByCoord)[coords] = new_node
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m.Nodes = append(m.Nodes, new_node)
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node.Up = new_node
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new_node.Down = node
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break
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}
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}
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}
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func lookupNeighbourLeft(raw_maze *reader.RawMaze, node *maze.Node, nodesByCoord *map[maze.Coordinates]*maze.Node) {
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for x := node.Coords.X - 1; x > 0; x-- {
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if raw_maze.IsWall(x, node.Coords.Y) && x < node.Coords.X-1 {
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panic(fmt.Sprintf("Found no node before wall while looking to the left at neighbours of node %v (arrived at x=%v before hitting a wall)", node, x))
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}
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neighbour, ok := (*nodesByCoord)[maze.Coordinates{X: x, Y: node.Coords.Y}]
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if ok {
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node.Left = neighbour
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neighbour.Right = node
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break
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}
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}
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}
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func lookupNeighbourRight(raw_maze *reader.RawMaze, node *maze.Node, nodesByCoord *map[maze.Coordinates]*maze.Node) {
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for x := node.Coords.X + 1; x < raw_maze.Width; x++ {
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if raw_maze.IsWall(x, node.Coords.Y) {
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panic(fmt.Sprintf("Found no node before wall while looking to the right at neighbours of node %v", node))
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}
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neighbour, ok := (*nodesByCoord)[maze.Coordinates{X: x, Y: node.Coords.Y}]
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if ok {
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node.Right = neighbour
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neighbour.Left = node
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break
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}
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}
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}
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