From 6c0337ad85333d7cd3252fbcbc5ac8af284806cf Mon Sep 17 00:00:00 2001
From: alexo <the.onga@gmail.com>
Date: Sun, 24 Dec 2023 00:17:58 +1100
Subject: [PATCH] day23: part2 find edges

---
 day23/day23.py            |  94 ++++----------------------
 day23/lib/classes.py      | 106 +++++++++++++++++++++++++++++-
 day23/lib/classes2.py     | 135 ++++++++++++++++++++++++++++++++++++++
 day23/lib/parsers.py      |   4 +-
 day23/tests/test_day23.py |   5 +-
 5 files changed, 255 insertions(+), 89 deletions(-)
 create mode 100644 day23/lib/classes2.py

diff --git a/day23/day23.py b/day23/day23.py
index bdc34e7..5457c5d 100644
--- a/day23/day23.py
+++ b/day23/day23.py
@@ -1,93 +1,22 @@
-from queue import Queue
-from typing import Optional
-
-from day23.lib.classes import Maze, Path, Position
+from day23.lib.classes import Maze, Path, Solver, Solver1
+from day23.lib.classes2 import Solver2
 from day23.lib.parsers import get_maze
 
 INPUT = "day23/input.txt"
 INPUT_SMALL = "day23/input-small.txt"
 
 
-class Solver:
-    maze: Maze
-    handle_hills: bool
-
-    def __init__(self, maze: Maze, handle_hills: bool = True) -> None:
-        self.maze = maze
-        self.handle_hills = handle_hills
-
-    def solve(self) -> list[Path]:
-        paths: Queue[Path] = Queue()
-        first_path = Path()
-        first_path.add(Position(0, 1))
-        paths.put(first_path)
-        # bfs all paths simultaneously
-        results: list[Path] = []
-        while not paths.empty():
-            path = paths.get()
-            if path.last().row == self.maze.num_rows - 1:
-                results.append(path)
-                continue
-
-            for expansion in self.expand_path(path):
-                paths.put(expansion)
-        return results
-
-    def expand_hill(self, position: Position, tile: str) -> list[Position]:
-        if tile == "^":
-            return [position.copy_modify(row=-1)]
-        elif tile == "v":
-            return [position.copy_modify(row=+1)]
-        elif tile == "<":
-            return [position.copy_modify(col=-1)]
-        elif tile == ">":
-            return [position.copy_modify(col=+1)]
-        else:
-            return position.expand()
-
-    def expand_path(self, path: Path) -> list[Path]:
-        current_pos: Position = path.last()
-        current_tile: Optional[str] = self.maze[current_pos]
-        if current_tile is None:
-            raise ValueError("there's no shot we got a tile outside the maze")
-        expansions: list[Position]
-        if self.handle_hills:
-            expansions = self.expand_hill(current_pos, current_tile)
-        else:
-            expansions = current_pos.expand()
-
-        valid_expansions = []
-        for expansion in expansions:
-            expansion_tile = self.maze[expansion]
-            if (
-                path.can_add(expansion)
-                and expansion_tile is not None
-                and expansion_tile != "#"
-            ):
-                valid_expansions.append(expansion)
-
-        if len(valid_expansions) == 0:
-            return []
-        elif len(valid_expansions) == 1:
-            path.add(valid_expansions[0])
-            return [path]
-        else:
-            result = []
-            for expansion in valid_expansions[1:]:
-                new_path = path.copy()
-                new_path.add(expansion)
-                result.append(new_path)
-            path.add(valid_expansions[0])
-            result.append(path)
-            return result
+def part1(maze: Maze) -> int:
+    solver = Solver1(maze, True)
+    return run_solver(solver)
 
 
-def part1(maze: Maze) -> int:
-    return solve(maze, True)
+def part2(maze: Maze) -> int:
+    solver = Solver2(maze)
+    return run_solver(solver)
 
 
-def solve(maze: Maze, handle_hills: bool) -> int:
-    solver = Solver(maze, handle_hills)
+def run_solver(solver: Solver) -> int:
     paths: list[Path] = solver.solve()
     path_lengths = [len(path) for path in paths]
     path_lengths.sort(reverse=True)
@@ -95,9 +24,10 @@ def solve(maze: Maze, handle_hills: bool) -> int:
 
 
 def main() -> None:
-    maze: Maze = get_maze(INPUT)
+    maze: Maze = get_maze(INPUT_SMALL)
 
-    print(part1(maze))
+    # print(part1(maze))
+    print(part2(maze))
 
 
 if __name__ == "__main__":
diff --git a/day23/lib/classes.py b/day23/lib/classes.py
index 663a338..21a30ab 100644
--- a/day23/lib/classes.py
+++ b/day23/lib/classes.py
@@ -1,4 +1,5 @@
 from dataclasses import dataclass
+from queue import Queue
 from typing import Optional
 
 
@@ -55,6 +56,11 @@ def copy(self) -> "Path":
         result.nodes = set(result.route)
         return result
 
+    def flip(self) -> "Path":
+        result = self.copy()
+        result.route.reverse()
+        return result
+
     def last(self) -> Position:
         if len(self.route) == 0:
             raise ValueError("Don't call last when i'm empty 4head")
@@ -74,17 +80,17 @@ def __len__(self) -> int:
 
 
 class Maze:
-    grid: list[str]  # 2d array of chars
+    grid: list[list[str]]  # 2d array of chars
     num_rows: int
     num_cols: int
 
-    def __init__(self, data: list[str]) -> None:
+    def __init__(self, data: list[list[str]]) -> None:
         self.grid = data
         self.num_rows = len(data)
         self.num_cols = len(data[0])
 
     def __str__(self) -> str:
-        return "\n".join(row for row in self.grid)
+        return "\n".join("".join(col for col in row) for row in self.grid)
 
     def __getitem__(self, position: Position) -> Optional[str]:
         """Get item via position. Returns None if out of bounds"""
@@ -94,6 +100,14 @@ def __getitem__(self, position: Position) -> Optional[str]:
             return None
         return self.grid[position.row][position.col]
 
+    def __setitem__(self, position: Position, value: str) -> None:
+        """Get item via position. Returns None if out of bounds"""
+        if not isinstance(position, Position):
+            raise ValueError(f"position is not a Position, {type(position)}")
+        if self.is_oob(position):
+            raise ValueError("can't set outside our maze!")
+        self.grid[position.row][position.col] = value
+
     def is_oob(self, position: Position) -> bool:
         """true if position is out of bounds"""
         return (
@@ -102,3 +116,89 @@ def is_oob(self, position: Position) -> bool:
             or position.col < 0
             or position.col >= self.num_cols
         )
+
+
+class Solver:
+    def solve(self) -> list[Path]:
+        return []
+
+
+class Solver1(Solver):
+    maze: Maze
+    handle_hills: bool
+
+    def __init__(self, maze: Maze, handle_hills: bool = True) -> None:
+        self.maze = maze
+        self.handle_hills = handle_hills
+
+    def solve(self) -> list[Path]:
+        paths: Queue[Path] = Queue()
+        first_path = Path()
+        first_path.add(Position(0, 1))
+        paths.put(first_path)
+        # bfs all paths simultaneously
+        results: list[Path] = []
+        count = 1
+        while not paths.empty():
+            path = paths.get()
+            if path.last().row == self.maze.num_rows - 1:
+                results.append(path)
+                continue
+
+            expansions = self.expand_path(path)
+            for expansion in expansions:
+                paths.put(expansion)
+            count += 1
+            if count % 1000 == 0:
+                print(count)
+
+        return results
+
+    def expand_hill(self, position: Position, tile: str) -> list[Position]:
+        if tile == "^":
+            return [position.copy_modify(row=-1)]
+        elif tile == "v":
+            return [position.copy_modify(row=+1)]
+        elif tile == "<":
+            return [position.copy_modify(col=-1)]
+        elif tile == ">":
+            return [position.copy_modify(col=+1)]
+        else:
+            return position.expand()
+
+    def expand_path(self, path: Path) -> list[Path]:
+        current_pos: Position = path.last()
+        current_tile: Optional[str] = self.maze[current_pos]
+        if current_tile is None:
+            raise ValueError("there's no shot we got a tile outside the maze")
+        expansions: list[Position]
+        if self.handle_hills:
+            expansions = self.expand_hill(current_pos, current_tile)
+        else:
+            expansions = current_pos.expand()
+
+        valid_expansions = []
+        for expansion in expansions:
+            expansion_tile = self.maze[expansion]
+            if (
+                path.can_add(expansion)
+                and expansion_tile is not None
+                and expansion_tile != "#"
+            ):
+                valid_expansions.append(expansion)
+
+        if len(valid_expansions) == 0:
+            return []
+        elif len(valid_expansions) == 1:
+            path.add(valid_expansions[0])
+            return [path]
+        else:
+            result = []
+            for expansion in valid_expansions[1:]:
+                new_path = path.copy()
+                new_path.add(expansion)
+                result.append(new_path)
+            path.add(valid_expansions[0])
+            result.append(path)
+
+            return result
diff --git a/day23/lib/classes2.py b/day23/lib/classes2.py
new file mode 100644
index 0000000..9a759b1
--- /dev/null
+++ b/day23/lib/classes2.py
@@ -0,0 +1,135 @@
+"""part 2 solution"""
+from dataclasses import dataclass, field
+from queue import Queue
+
+import colorama
+
+from day23.lib.classes import Maze, Path, Position, Solver
+
+
+# first simplify graph to "nodes", then brute force that.
+@dataclass
+class Node:
+    name: int
+    position: Position
+    edges: list["Edge"] = field(default_factory=list)
+
+    def __str__(self) -> str:
+        return f"{self.name}: ({self.position}) {[str(edge) for edge in self.edges]}"
+
+
+@dataclass
+class Edge:
+    node1: int
+    node2: int
+    path: Path = field(repr=False)
+
+    def flip(self) -> "Edge":
+        return Edge(self.node2, self.node1, self.path.flip())
+
+    def __str__(self) -> str:
+        return f"{self.node1}->{self.node2}, {len(self.path)}"
+
+
+class Solver2(Solver):
+    maze: Maze
+
+    def __init__(self, maze: Maze) -> None:
+        self.maze = maze
+
+    def get_cell_branches(self, position: Position) -> int:
+        result = 0
+        if self.maze[position] != ".":
+            return 0
+        for direction in position.expand():
+            tile = self.maze[direction]
+            if tile is not None and tile != "#":
+                result += 1
+        return result
+
+    def get_nodes(self) -> dict[Position, Node]:
+        nodes: list[Node] = []
+
+        start = Position(0, 1)
+        nodes.append(Node(0, start))
+        name = 1
+        for row in range(self.maze.num_rows):
+            for col in range(self.maze.num_cols):
+                pos = Position(row, col)
+                if self.get_cell_branches(pos) > 2:
+                    node = Node(name, pos)
+                    name += 1
+                    nodes.append(node)
+
+        # add start and end coz they are dumb
+
+        end = Position(self.maze.num_rows - 1, self.maze.num_cols - 2)
+
+        nodes.append(Node(name, end))
+        for node in nodes:
+            self.maze[node.position] = (
+                colorama.Back.GREEN + str(node.name) + colorama.Back.BLACK
+            )
+        return {node.position: node for node in nodes}
+
+    def fill_node(self, start_node: Node, nodes: dict[Position, Node]) -> None:
+        first_path = Path()
+        first_path.add(start_node.position)
+        paths: Queue[Path] = Queue()
+        paths.put(first_path)
+        while not paths.empty():
+            path = paths.get()
+            pos = path.last()
+            if pos != start_node.position and pos in nodes:
+                # reached an edge
+                edge = Edge(start_node.name, nodes[pos].name, path)
+                start_node.edges.append(edge)
+                end_node = nodes[pos]
+                end_node.edges.append(edge.flip())
+                continue
+            expansions = self.expand_path(path)
+            for path in expansions:
+                paths.put(path)
+
+    def expand_path(self, path: Path) -> list[Path]:
+        current_pos: Position = path.last()
+        expansions = current_pos.expand()
+
+        valid_expansions = []
+        for expansion in expansions:
+            expansion_tile = self.maze[expansion]
+            if (
+                path.can_add(expansion)
+                and expansion_tile is not None
+                and expansion_tile != "#"
+            ):
+                valid_expansions.append(expansion)
+                if expansion_tile == ".":
+                    self.maze[expansion] = "#"
+
+        if len(valid_expansions) == 0:
+            return []
+        elif len(valid_expansions) == 1:
+            path.add(valid_expansions[0])
+            return [path]
+        else:
+            result = []
+            for expansion in valid_expansions[1:]:
+                new_path = path.copy()
+                new_path.add(expansion)
+                result.append(new_path)
+            path.add(valid_expansions[0])
+            result.append(path)
+
+            return result
+
+    def solve(self) -> list[Path]:
+        nodes: dict[Position, Node] = self.get_nodes()
+        print(self.maze)
+        for node in nodes.values():
+            self.fill_node(node, nodes)
+
+        for node in nodes.values():
+            print(node)
+
+        return []
diff --git a/day23/lib/parsers.py b/day23/lib/parsers.py
index 89b759b..47be223 100644
--- a/day23/lib/parsers.py
+++ b/day23/lib/parsers.py
@@ -2,7 +2,7 @@
 
 
 def get_maze(path: str) -> Maze:
-    rows: list[str] = []
+    rows: list[list[str]] = []
     with open(path, encoding="utf8") as file:
-        rows = [line.strip() for line in file]
+        rows = [list(line.strip()) for line in file]
     return Maze(rows)
diff --git a/day23/tests/test_day23.py b/day23/tests/test_day23.py
index 0f381b9..6208a82 100644
--- a/day23/tests/test_day23.py
+++ b/day23/tests/test_day23.py
@@ -1,6 +1,7 @@
 from typing import TYPE_CHECKING
 
-from day23.day23 import INPUT_SMALL, Solver, part1
+from day23.day23 import INPUT_SMALL, part1
+from day23.lib.classes import Solver1
 from day23.lib.parsers import get_maze
 
 if TYPE_CHECKING:
@@ -10,7 +11,7 @@
 def test_solver() -> None:
     maze: Maze = get_maze(INPUT_SMALL)
 
-    solver = Solver(maze)
+    solver = Solver1(maze)
     paths: list[Path] = solver.solve()
 
     path_lengths = [len(path) for path in paths]