[2] add solving methods

meosyam/docs/data/2/main.py

@@ -1,4 +1,9 @@
 import sys
+import time
+from collections import deque
+import heapq
+from dataclasses import dataclass
+
 
 class Cell:
     def __init__(self, x, y, is_wall=False, is_start=False, is_exit=False):
@@ -70,12 +75,138 @@ class MazeBuilder:
         return Maze(width, height, cells, start, exit_cell)
 
 
-def print_maze(maze):
+class PathFindingStrategy:
+    def find_path(self, maze, start, exit):
+        raise NotImplementedError
+
+
+class BFSStrategy(PathFindingStrategy):
+    def find_path(self, maze, start, exit):
+        if start == exit:
+            return [start], 1
+        queue = deque([start])
+        visited = {start}
+        parent = {start: None}
+        visited_count = 1
+        while queue:
+            current = queue.popleft()
+            if current == exit:
+                path = []
+                while current:
+                    path.append(current)
+                    current = parent[current]
+                path.reverse()
+                return path, visited_count
+            for neighbor in maze.get_neighbors(current):
+                if neighbor not in visited:
+                    visited.add(neighbor)
+                    parent[neighbor] = current
+                    queue.append(neighbor)
+                    visited_count += 1
+        return [], visited_count
+
+
+class DFSStrategy(PathFindingStrategy):
+    def find_path(self, maze, start, exit):
+        if start == exit:
+            return [start], 1
+        stack = [start]
+        visited = {start}
+        parent = {start: None}
+        visited_count = 1
+        while stack:
+            current = stack.pop()
+            if current == exit:
+                path = []
+                while current:
+                    path.append(current)
+                    current = parent[current]
+                path.reverse()
+                return path, visited_count
+            for neighbor in maze.get_neighbors(current):
+                if neighbor not in visited:
+                    visited.add(neighbor)
+                    parent[neighbor] = current
+                    stack.append(neighbor)
+                    visited_count += 1
+        return [], visited_count
+
+
+class AStarStrategy(PathFindingStrategy):
+    @staticmethod
+    def manhattan(cell, target):
+        return abs(cell.x - target.x) + abs(cell.y - target.y)
+
+    def find_path(self, maze, start, exit):
+        if start == exit:
+            return [start], 1
+        open_set = []
+        counter = 0
+        heapq.heappush(open_set, (0, counter, start))
+        g_score = {start: 0}
+        f_score = {start: self.manhattan(start, exit)}
+        parent = {start: None}
+        visited_count = 0
+        visited = set()
+        while open_set:
+            _, _, current = heapq.heappop(open_set)
+            if current in visited:
+                continue
+            visited.add(current)
+            visited_count += 1
+            if current == exit:
+                path = []
+                while current:
+                    path.append(current)
+                    current = parent[current]
+                path.reverse()
+                return path, visited_count
+            for neighbor in maze.get_neighbors(current):
+                tentative_g = g_score[current] + 1
+                if neighbor not in g_score or tentative_g < g_score[neighbor]:
+                    parent[neighbor] = current
+                    g_score[neighbor] = tentative_g
+                    f = tentative_g + self.manhattan(neighbor, exit)
+                    f_score[neighbor] = f
+                    counter += 1
+                    heapq.heappush(open_set, (f, counter, neighbor))
+        return [], visited_count
+
+
+@dataclass
+class SearchStats:
+    time_ms: float
+    visited_cells: int
+    path_length: int
+
+
+class MazeSolver:
+    def __init__(self, maze, strategy=None):
+        self.maze = maze
+        self.strategy = strategy
+
+    def set_strategy(self, strategy):
+        self.strategy = strategy
+
+    def solve(self):
+        if self.strategy is None:
+            raise ValueError("Strategy not set")
+        start_time = time.perf_counter()
+        path, visited = self.strategy.find_path(self.maze, self.maze.start, self.maze.exit)
+        end_time = time.perf_counter()
+        time_ms = (end_time - start_time) * 1000
+        return path, SearchStats(time_ms, visited, len(path) if path else 0)
+
+
+def print_maze(maze, path=None):
+    path_set = set(path) if path else set()
     for y in range(maze.height):
         row = []
         for x in range(maze.width):
             cell = maze.get_cell(x, y)
-            if cell.is_start:
+            if cell in path_set and not cell.is_start and not cell.is_exit:
+                row.append('*')
+            elif cell.is_start:
                 row.append('S')
             elif cell.is_exit:
                 row.append('E')
@@ -91,10 +222,33 @@ def main():
         filename = sys.argv[1]
     else:
         filename = 'maze1.txt'
+
     try:
         maze = MazeBuilder.build_from_file(filename)
         print(f"Maze loaded ({maze.width}x{maze.height})")
-        print_maze(maze)
+        print("Select algorithm: (1) BFS, (2) DFS, (3) A*")
+        choice = input("Choice: ").strip()
+        if choice == '1':
+            strategy = BFSStrategy()
+        elif choice == '2':
+            strategy = DFSStrategy()
+        elif choice == '3':
+            strategy = AStarStrategy()
+        else:
+            print("Invalid, using BFS")
+            strategy = BFSStrategy()
+
+        solver = MazeSolver(maze, strategy)
+        path, stats = solver.solve()
+        if path:
+            print(f"Path found! Length: {len(path)}")
+            print(f"Visited cells: {stats.visited_cells}")
+            print(f"Time: {stats.time_ms:.4f} ms")
+            print_maze(maze, path)
+        else:
+            print("No path found.")
+            print(f"Visited cells: {stats.visited_cells}")
+            print(f"Time: {stats.time_ms:.4f} ms")
     except Exception as e:
         print(f"Error: {e}")