refactor part 1

day10/day10.py

@@ -50,25 +50,26 @@ class Tile(object):
             self.links = [S, E]    
 
     def __str__(self):
-        return self.val
+        return f'{self.val} x: {self.x} y: {self.y}'
 
-    def opposite_end(self, d: Direction) -> Direction:
-        entry = d.opposite()
-        if not entry in self.links:
+    def __eq__(self, obj) -> bool:
+        return self.x == obj.x and self.y == obj.y
+
+    def __hash__(self):
+        return hash((self.x, self.y))
+
+    def opposite_pipe_end(self, d: Direction) -> Direction:
+        if not d in self.links:
             return None
-        if entry == self.links[0]:
+        if d == self.links[0]:
             return self.links[1]
         else:
             return self.links[0]
 
     def has_link_from(self, d: Direction) -> bool:
-        return (d.opposite() in self.links)
+        return (d in self.links)
         
 
-    def is_pipe(self):
-        return self.val != '.'
-
-
 class Field(object):
     def __init__(self, lines: list[str]):
         self.grid = [list(l) for l in lines]
@@ -82,77 +83,94 @@ class Field(object):
             out += ''.join([str(tile) for tile in row]) + '\n'
         return out
 
-    def get(self, x, y: int) -> Tile:
-        if y >= len(self.grid) or x >= len(self.grid):
+    def _get(self, x, y: int) -> Tile:
+        if y < 0 or x < 0 or y >= len(self.grid) or x >= len(self.grid):
             return None
         return  self.grid[y][x]
 
+    def get_adjacent(self, t: Tile, d: Direction) -> Tile:
+        x, y = t.x, t.y
+        if d == E:
+            x += 1
+        elif d == S:
+            y += 1
+        elif d == W:
+            x -= 1
+        elif d == N:
+            y -= 1
+        return self._get(x, y)
+
+        
+
         
 class Walker(Field):
     def __init__(self, lines):
         super().__init__(lines)
+        self.loop = []
+        self.visited = set()
         
     def _get_start(self) -> Tile:
         for y in range(len(self.grid)):
             for x in range(len(self.grid[0])):
-                t = self.get(x, y)
+                t = self._get(x, y)
                 if t.val == START:
                     return t
         return None
 
-    def _walk_to_start(self, t: Tile, direction: Direction) -> (bool, int):
-        self.visited = set()
-        steps = 0
-        while True:
-            x, y = t.x, t.y
-            self.visited.add((x, y))
-            if direction == E:
-                x += 1
-            elif direction == S:
-                y += 1
-            elif direction == W:
-                x -= 1
-            elif direction == N:
-                y -= 1
-            nxt = self.get(x, y)
-            if (not nxt):
-                break
-
-            steps += 1
-            if nxt.val == START:
-                return True, steps
-            if not nxt.has_link_from(direction):
-                break
-
-            t = nxt
-            d = nxt.opposite_end(direction)
-            direction = d
-        return False, steps
+    def _find_loop(self):
+        start = self._get_start()
+        for d in [N, E, S, W]:
+            curr = start
+            dir = d
+            self.loop = []
+            while True:
+                self.loop.append(curr)
+                nxt = self.get_adjacent(curr, dir)
+                if not nxt or not nxt.has_link_from(dir.opposite()):
+                    break
+                if nxt.val == START:
+                    return
+                curr = nxt
+                dir = nxt.opposite_pipe_end(dir.opposite())
 
 
     def find_max_steps_in_loop(self) -> int:
-        start = self._get_start()
-        for direction in [N, E, S, W]:
-            found, steps = self._walk_to_start(start, direction)
-            if found:
-                return steps // 2
+        self._find_loop()
+        return len(self.loop) // 2
 
     def find_captured_by_loop(self) -> int:
-        if not self.visited:
-            self.find_max_steps_in_loop()
-        pass
+        if not self.loop:
+            # this fills self.loop slice
+            # with loop tiles
+            self._find_loop()
+        self.visited = set(self.loop)
+        inside_loop = set()
+        for t in self.loop:
+            for d in [N, E, S, W]:
+                newt = self.get_adjacent(t, d)
+                if not newt or newt in self.visited:
+                    continue
+                if self._is_inside_loop(newt):
+                    inside_loop.add(newt)
+                self.visited.add(newt)
+        return len(inside_loop)
+
+
+    def _is_inside_loop(self, t: Tile) -> bool:
+        # TODO
+        return True
+            
 
-                
                 
 if __name__ == '__main__':
     r = tools.Reader('test_input.txt')
     lines = r.read()
 
     w = Walker(lines)
-    print(w)
     steps = w.find_max_steps_in_loop()
     print(steps)
-    print(w.visited)
+    n = w.find_captured_by_loop()
+    print(n)
 
     r = tools.Reader('input.txt')
     lines = r.read()
@@ -160,5 +178,5 @@ if __name__ == '__main__':
     w = Walker(lines)
     steps = w.find_max_steps_in_loop()
     print(steps)
-    # print(w.visited)
+    # print(w.loop)