update: Extract Breadth-first search and Depth-first search algorithm…

… onto general function _search

src/pathfinding/algorithms.py

@@ -1,7 +1,7 @@
 """algorithms.py module"""
 
 import time
-from queue import PriorityQueue
+from queue import PriorityQueue, Queue, LifoQueue
 
 from . import cubes
 
@@ -140,97 +140,61 @@ def astar(app_scene, cube, paths):  # Thread
     return False, len(visited), 0, 0
 
 
-def dfs(app_scene, cube: cubes.CharacterCube, paths: cubes.PathCubeList) -> bool:
-    """Finds a path from the starting node to the end node.
-
-    The start node is defined by the current cube's position and the
-    end node is defined by the pathcube which its is_objective attribute is true.
-
-    The algorithm finds a path using the depth-first search algorithm.
-
-    Returns:
-        True if the a path was found, othewise False.
-    """
+def _search(app_scene, cube: cubes.CharacterCube, paths: cubes.PathCubeList, container_class):
+    """General function for searching."""
+    start_node = paths.find_path(cube)
+    came_from = {}
 
+    queue = container_class()
     visited = set()
+    queue.put(start_node)
 
-    start = paths.find_path(cube)
-    path = [start]
-    # stack item: pathcube path
-    stack = [(start, path)]
+    start_node.rect_colour = (255, 0, 255)
+
+    while not queue.empty():
+        current_node = queue.get()
 
-    while stack:
         if not app_scene.traversing:
             break
 
-        c_pathcube, c_path = stack.pop()
-
-        if c_pathcube in visited:
+        if current_node.is_objective:
+            path = reconstruct_path(came_from, current_node)
+            return (walk(app_scene, cube, path), len(visited), len(path),
+                    sum(map(lambda p: p.weight, path)))
+        elif current_node in visited:
             continue
-        if c_pathcube.is_objective:
-            # A path was found. Animate it
-            return (walk(app_scene, cube, c_path), len(visited), len(c_path),
-                    sum(map(lambda p: p.weight, c_path)))
-
-        for neighbour in paths.get_neighbors(c_pathcube):
-            if not neighbour.is_blocked:    
-                next_path = c_path + [neighbour]
-                stack.append((neighbour, next_path))
+
+        for neighbour in paths.get_neighbors(current_node):
+            if not (neighbour.is_blocked or neighbour in visited):
+                queue.put(neighbour)
+                came_from[neighbour] = current_node
                 neighbour.rect_color = (180, 0, 0)
-
-        c_pathcube.rect_color = (255, 0, 255)
-        visited.add(c_pathcube)
-        time.sleep(TIME_INTERVAL)
 
+        visited.add(current_node)
+        current_node.rect_color = (255, 0, 255)
+        time.sleep(TIME_INTERVAL)
     return False, len(visited), 0, 0
 
 
-def bfs(app_scene, cube: cubes.CharacterCube, paths: cubes.PathCubeList) -> bool:
+def dfs(app_scene, cube: cubes.CharacterCube, paths: cubes.PathCubeList) -> bool:
     """Finds a path from the starting node to the end node.
 
     The start node is defined by the current cube's position and the
     end node is defined by the pathcube which its is_objective attribute is true.
 
-    The algorithm finds a path using the breadth-first search algorithm.
+    The algorithm finds a path using the depth-first search algorithm.
 
     Returns:
         True if the a path was found, othewise False.
     """
 
-    visited = set()
+    return _search(app_scene, cube, paths, LifoQueue)
 
-    start = paths.find_path(cube)
-    path = [start]
-    # stack item: pathcube path
-    stack = [(start, path)]
 
-    while stack:
-        if not app_scene.traversing:
-            break
-
-        c_pathcube, c_path = stack.pop(0)
+def bfs(app_scene, cube: cubes.CharacterCube, paths: cubes.PathCubeList):
+    """Breadth-first search algorithm."""
 
-        if c_pathcube in visited:
-            continue
-        else:
-            visited.add(c_pathcube)
-
-        if c_pathcube.is_objective:
-            # A path was found. Animate it
-            return (walk(app_scene, cube, c_path), len(visited), len(c_path),
-                    sum(map(lambda p: p.weight, c_path)))
-
-        for neighbour in paths.get_neighbors(c_pathcube):
-            if not neighbour.is_blocked:
-                next_path = c_path + [neighbour]
-                stack.append((neighbour, next_path))
-            neighbour.rect_color = (180, 0, 0)
-
-        c_pathcube.rect_color = (255, 0, 255)
-
-        time.sleep(TIME_INTERVAL)
-
-    return False, len(visited), 0, 0
+    return _search(app_scene, cube, paths, Queue)
 
 
 def dijkstra(app_scene, cube: cubes.CharacterCube, paths: cubes.PathCubeList):