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class Maze | |
def initialize(maze_string) | |
@maze = maze_string.split("\n") | |
@maze = @maze.map do |maze| | |
maze_row = [] | |
maze.each_char do |c| | |
maze_row << { | |
:is_wall => (c == "#"), | |
:dist_A => (c == "A" ? 0 : nil), | |
:dist_B => (c == "B" ? 0 : nil) | |
} | |
end | |
maze_row | |
end | |
@maze_string = maze_string | |
end | |
def solvable? | |
true | |
end | |
def rows | |
@maze.size | |
end | |
def cols | |
@maze[0].size | |
end | |
def position_A | |
row, col = position("A") | |
position("A") | |
end | |
def position_B | |
row, col = position("B") | |
position("B") | |
end | |
def find_non_wall_neighbor(row, col) | |
[ | |
neighbor(row-1, col), | |
neighbor(row, col+1), | |
neighbor(row+1, col), | |
neighbor(row, col-1) | |
].compact | |
end | |
def neighbor(row, col) | |
row_col_within_bounds(row, col) && @maze[row][col][:is_wall] != true ? [row, col] : nil | |
end | |
def row_col_within_bounds(row, col) | |
0 <= row && rows >= row && 0 <= col && cols >= col | |
end | |
def position(str) | |
pos = @maze_string.index(str) | |
return pos/(cols+1), (pos % (cols+1) ) | |
end | |
def solvable? | |
solvable, steps = solve | |
solvable | |
end | |
def steps | |
solvable, steps = solve | |
steps | |
end | |
def solve | |
nearest_neighbors_a = [position_A] | |
nearest_neighbors_b = [position_B] | |
solvable = false | |
steps = 0 | |
while (!nearest_neighbors_a.empty? || !nearest_neighbors_b.empty?) | |
solvable, steps, nearest_neighbors_a = take_one_step("A", nearest_neighbors_a) | |
solvable, steps, nearest_neighbors_b = take_one_step("B", nearest_neighbors_b) | |
break if solvable | |
end | |
return solvable, steps | |
end | |
def take_one_step(str_node, nearest_neighbors) | |
other_node = str_node == "A" ? "B" : "A" | |
new_nearest_neighbors = [] | |
solvable = false | |
steps = 0 | |
nearest_neighbors.each do |neighbor| | |
neighbor_node = @maze[neighbor[0]][neighbor[1]] | |
node_neighbors_coords = find_non_wall_neighbor(neighbor[0], neighbor[1]) | |
node_neighbors_coords.each do |current_node_coords| | |
current_node = @maze[current_node_coords[0]][current_node_coords[1]] | |
current_node[:row] = current_node_coords[0] | |
current_node[:col] = current_node_coords[1] | |
# see if its already near other node, if yes hurray! | |
if !current_node["dist_#{other_node}".to_sym].nil? | |
solvable, steps = true, 1 + current_node["dist_#{other_node}".to_sym] + | |
neighbor_node["dist_#{str_node}".to_sym] | |
break | |
elsif current_node["dist_#{str_node}".to_sym].nil? | |
current_node["dist_#{str_node}".to_sym] = neighbor_node["dist_#{str_node}".to_sym] + 1 | |
new_nearest_neighbors << current_node_coords | |
end | |
end | |
break if solvable | |
end | |
return solvable, steps, new_nearest_neighbors | |
end | |
end | |
require 'test/unit' | |
require 'maze' | |
MAZE1 = %{##################################### | |
# # # #A # # # | |
# # # # # # ####### # ### # ####### # | |
# # # # # # # # # | |
# ##### # ################# # ####### | |
# # # # # # # # # | |
##### ##### ### ### # ### # # # # # # | |
# # # # # # B# # # # # # | |
# # ##### ##### # # ### # # ####### # | |
# # # # # # # # # # # # | |
# ### ### # # # # ##### # # # ##### # | |
# # # # # # # | |
#####################################} | |
# Maze 1 should SUCCEED | |
MAZE2 = %{##################################### | |
# # # # # # | |
# ### ### # ########### ### # ##### # | |
# # # # # # # # # # | |
# # ###A##### # # # # ### ########### | |
# # # # # # # # # | |
####### # ### ####### # ### ####### # | |
# # # # # # # # | |
# ####### # # # ####### # ##### # # # | |
# # # # # # # # # # # | |
# ##### # # ##### ######### # ### # # | |
# # # # #B# | |
#####################################} | |
# Maze 2 should SUCCEED | |
MAZE3 = %{##################################### | |
# # # # # | |
# ### # ####### # # # ############# # | |
# # # # # # # # # # | |
### ##### ### ####### # ##### ### # # | |
# # # # A # # # # # | |
# ######### ##### # ####### ### ### # | |
# ### # # # # # | |
# ### ### ####### ####### # # # # ### | |
# # # # # #B# # # # # # # | |
# # # ##### ### # # # # ### # ##### # | |
# # # # # # | |
#####################################} | |
# Maze 3 should FAIL | |
class MazeTest < Test::Unit::TestCase | |
def test_good_mazes | |
assert_equal true, Maze.new(MAZE1).solvable? | |
assert_equal true, Maze.new(MAZE2).solvable? | |
end | |
def test_bad_mazes | |
assert_equal false, Maze.new(MAZE3).solvable? | |
end | |
def test_maze_steps | |
assert_equal 44, Maze.new(MAZE1).steps | |
assert_equal 75, Maze.new(MAZE2).steps | |
assert_equal 0, Maze.new(MAZE3).steps | |
end | |
def test_find_non_wall_neighbor | |
good_maze = Maze.new(MAZE1) | |
assert_equal [], good_maze.find_non_wall_neighbor(0, 0) | |
assert_equal [[5, 1]], good_maze.find_non_wall_neighbor(5, 0) | |
assert_equal [[1, 14]], good_maze.find_non_wall_neighbor(1, 13) | |
assert_equal [[1,9], [3,9]], good_maze.find_non_wall_neighbor(2, 9) | |
end | |
end |
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