DFS implementation of the classic maze

DFSSwift.maze

struct Pixel {
  var color: Color
  var isExit: Bool
  init(color: Color, isExit: Bool = false) {
    self.color = color
    self.isExit = isExit
  }
}

enum Color {
  case white
  case black
}

struct Position {
  var row: Int
  var col: Int
}


func findPath(maze: [[Pixel]], entrance: Position) -> [Position] {
  var path: [Position] = []
  var visited: [[Bool]] = Array(repeating: Array(repeating: false, count:maze.count), count: maze.count)
  path.append(entrance)
  visited[entrance.row][entrance.col] = true
  if (dfs(maze:maze, curPos:entrance, path:&path, visited:&visited)) {
    return path
  }
  return []
}

func dfs(maze: [[Pixel]], curPos: Position, path: inout [Position], visited: inout [[Bool]]) -> Bool {
  if maze[curPos.row][curPos.col].isExit {
    return true
  } else {
    let neighbors = getNeighbors(maze:maze, curPos:curPos)
    for neighbor in neighbors {
      if !visited[neighbor.row][neighbor.col] {
        path.append(neighbor)
        visited[neighbor.row][neighbor.col] = true
        let foundPath = dfs(maze:maze, curPos:neighbor, path:&path, visited:&visited)
        if foundPath {
          return true
        }
        _ = path.removeLast()
        visited[neighbor.row][neighbor.col] = false
      }
    }
    return false
  }
}

func getNeighbors(maze:[[Pixel]], curPos:Position) -> [Position] {
  var neighbors:[Position] = []

    // right
  if curPos.col + 1 < maze.count && maze[curPos.row][curPos.col+1].color != .black {
    neighbors.append(Position(row: curPos.row, col: curPos.col+1))
  }
  
  // bottom
  if curPos.row + 1 < maze.count && maze[curPos.row+1][curPos.col].color != .black {
    neighbors.append(Position(row: curPos.row+1, col: curPos.col))
  }
  
  // top
  if curPos.row - 1 >= 0 && maze[curPos.row-1][curPos.col].color != .black {
    neighbors.append(Position(row: curPos.row - 1, col: curPos.col))
  }
    
  // left
  if curPos.col - 1 >= 0 && maze[curPos.row][curPos.col-1].color != .black {
    neighbors.append(Position(row: curPos.row, col: curPos.col-1))
  }
  
  return neighbors
}


var maze: [[Pixel]] = [
  [Pixel(color:.white), Pixel(color:.black), Pixel(color:.white)],
  [Pixel(color:.white), Pixel(color:.black), Pixel(color:.white)],
  [Pixel(color:.white), Pixel(color:.black), Pixel(color:.white, isExit: true)],
]

print(findPath(maze:maze, entrance: Position(row: 0, col: 0)))