Merge pull request #43 from ewdlop/ewdlop-patch-33

Create SokobanSolver.py

Author: ewdlop

Python/Claude/SokobanSolver.py

@@ -0,0 +1,231 @@
+import heapq
+from collections import deque
+from typing import List, Tuple, Dict, Set
+
+class SokobanState:
+    """Represents a state in the Sokoban game"""
+    def __init__(self, player_pos: Tuple[int, int], boxes: Set[Tuple[int, int]], level: List[List[str]]):
+        self.player_pos = player_pos
+        self.boxes = frozenset(boxes)  # Use frozenset for hashing
+        self.level = level
+        self.goals = self._find_goals()
+        
+    def _find_goals(self) -> Set[Tuple[int, int]]:
+        """Find all goal positions in the level"""
+        goals = set()
+        for y, row in enumerate(self.level):
+            for x, cell in enumerate(row):
+                if cell in '.+*':
+                    goals.add((x, y))
+        return goals
+    
+    def is_goal_state(self) -> bool:
+        """Check if all boxes are on goal positions"""
+        return all(box in self.goals for box in self.boxes)
+    
+    def __hash__(self):
+        return hash((self.player_pos, self.boxes))
+    
+    def __eq__(self, other):
+        return self.player_pos == other.player_pos and self.boxes == other.boxes
+
+class SokobanSolver:
+    """Solves Sokoban puzzles using A* search algorithm"""
+    
+    def __init__(self, level: List[str]):
+        self.level = self._parse_level(level)
+        self.initial_state = self._create_initial_state()
+        self.moves = [(0, 1), (1, 0), (0, -1), (-1, 0)]  # down, right, up, left
+        self.move_names = ['D', 'R', 'U', 'L']
+        
+    def _parse_level(self, level: List[str]) -> List[List[str]]:
+        """Convert string level to 2D list"""
+        return [list(row) for row in level]
+    
+    def _create_initial_state(self) -> SokobanState:
+        """Create initial state from level"""
+        player_pos = None
+        boxes = set()
+        
+        for y, row in enumerate(self.level):
+            for x, cell in enumerate(row):
+                if cell in '@+':
+                    player_pos = (x, y)
+                if cell in '$*':
+                    boxes.add((x, y))
+        
+        return SokobanState(player_pos, boxes, self.level)
+    
+    def _is_wall(self, x: int, y: int) -> bool:
+        """Check if position is a wall"""
+        return self.level[y][x] == '#'
+    
+    def _is_valid_position(self, x: int, y: int) -> bool:
+        """Check if position is within bounds and not a wall"""
+        if x < 0 or x >= len(self.level[0]) or y < 0 or y >= len(self.level):
+            return False
+        return not self._is_wall(x, y)
+    
+    def _calculate_heuristic(self, state: SokobanState) -> int:
+        """Calculate heuristic (Manhattan distance from boxes to nearest goals)"""
+        if not state.goals:
+            return 0
+            
+        total_distance = 0
+        for box in state.boxes:
+            min_distance = float('inf')
+            for goal in state.goals:
+                distance = abs(box[0] - goal[0]) + abs(box[1] - goal[1])
+                min_distance = min(min_distance, distance)
+            total_distance += min_distance
+        
+        return total_distance
+    
+    def _get_successors(self, state: SokobanState) -> List[Tuple[SokobanState, str]]:
+        """Get possible next states and the moves that lead to them"""
+        successors = []
+        
+        for i, (dx, dy) in enumerate(self.moves):
+            # Calculate new player position
+            new_x = state.player_pos[0] + dx
+            new_y = state.player_pos[1] + dy
+            
+            if not self._is_valid_position(new_x, new_y):
+                continue
+            
+            # Check if player is pushing a box
+            box_pos = (new_x, new_y)
+            if box_pos in state.boxes:
+                # Calculate new box position
+                new_box_x = new_x + dx
+                new_box_y = new_y + dy
+                
+                # Check if box can be pushed
+                if not self._is_valid_position(new_box_x, new_box_y):
+                    continue
+                    
+                # Check if there's already a box at the new position
+                new_box_pos = (new_box_x, new_box_y)
+                if new_box_pos in state.boxes:
+                    continue
+                
+                # Create new state with pushed box
+                new_boxes = set(state.boxes)
+                new_boxes.remove(box_pos)
+                new_boxes.add(new_box_pos)
+                new_state = SokobanState((new_x, new_y), new_boxes, state.level)
+            else:
+                # Create new state with moved player
+                new_state = SokobanState((new_x, new_y), state.boxes, state.level)
+            
+            successors.append((new_state, self.move_names[i]))
+        
+        return successors
+    
+    def solve(self) -> List[str]:
+        """Solve the Sokoban puzzle using A* search"""
+        frontier = []
+        heapq.heappush(frontier, (0, 0, self.initial_state, []))
+        explored = set()
+        explored.add(self.initial_state)
+        
+        while frontier:
+            _, cost, current_state, moves = heapq.heappop(frontier)
+            
+            if current_state.is_goal_state():
+                return moves
+            
+            for next_state, move in self._get_successors(current_state):
+                if next_state not in explored:
+                    new_cost = cost + 1
+                    priority = new_cost + self._calculate_heuristic(next_state)
+                    heapq.heappush(frontier, (priority, new_cost, next_state, moves + [move]))
+                    explored.add(next_state)
+        
+        return []  # No solution found
+
+# Example usage
+def print_level(level):
+    """Print the level"""
+    for row in level:
+        print(''.join(row))
+    print()
+
+def apply_moves(level, moves):
+    """Apply a sequence of moves to the level"""
+    # Create a copy of the level as list of lists
+    current_level = [list(row) for row in level]
+    
+    # Find player position
+    player_pos = None
+    for y, row in enumerate(current_level):
+        for x, cell in enumerate(row):
+            if cell in '@+':
+                player_pos = (x, y)
+                break
+        if player_pos:
+            break
+    
+    # Define move directions
+    directions = {'D': (0, 1), 'R': (1, 0), 'U': (0, -1), 'L': (-1, 0)}
+    
+    for move in moves:
+        dx, dy = directions[move]
+        new_x, new_y = player_pos[0] + dx, player_pos[1] + dy
+        
+        # Check if player is pushing a box
+        if current_level[new_y][new_x] in '$*':
+            box_new_x, box_new_y = new_x + dx, new_y + dy
+            
+            # Update box position
+            if current_level[new_y][new_x] == '$':
+                current_level[new_y][new_x] = ' '
+            else:  # current_level[new_y][new_x] == '*'
+                current_level[new_y][new_x] = '.'
+            
+            if current_level[box_new_y][box_new_x] == '.':
+                current_level[box_new_y][box_new_x] = '*'
+            else:
+                current_level[box_new_y][box_new_x] = '$'
+        
+        # Update player position
+        if current_level[player_pos[1]][player_pos[0]] == '@':
+            current_level[player_pos[1]][player_pos[0]] = ' '
+        else:  # current_level[player_pos[1]][player_pos[0]] == '+'
+            current_level[player_pos[1]][player_pos[0]] = '.'
+        
+        if current_level[new_y][new_x] == '.':
+            current_level[new_y][new_x] = '+'
+        else:
+            current_level[new_y][new_x] = '@'
+        
+        player_pos = (new_x, new_y)
+        
+        print(f"Move: {move}")
+        print_level(current_level)
+    
+    return current_level
+
+# Test with a simple level
+if __name__ == "__main__":
+    # Simple example level
+    level = [
+        "#####",
+        "#@ $#",
+        "# . #",
+        "#   #",
+        "#####"
+    ]
+    
+    print("Initial level:")
+    print_level(level)
+    
+    solver = SokobanSolver(level)
+    solution = solver.solve()
+    
+    if solution:
+        print(f"Solution found: {solution}")
+        print("\nApplying solution:")
+        final_level = apply_moves(level, solution)
+    else:
+        print("No solution found!")