day05 finished

advent/days/day05/solution.py

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+from __future__ import annotations
+from dataclasses import dataclass
+
+from typing import Iterator
+
+from advent.parser.parser import P
+
+day_num = 5
+
+
+def part1(lines: Iterator[str]) -> str:
+    state = State.parse(lines)
+    crates = state.all_moves9000()
+    return State.top(crates)
+
+
+def part2(lines: Iterator[str]) -> str:
+    state = State.parse(lines)
+    crates = state.all_moves9001()
+    return State.top(crates)
+
+
+crate_parser: P[str | None] = P.either(P.any_char().in_brackets(), P.string("   ").replace(None))
+crate_row_parser = crate_parser.sep_by(P.is_char(' '))
+amount_parser = P.snd(P.string("move "), P.unsigned())
+from_parser = P.snd(P.string(" from "), P.unsigned())
+to_parser = P.snd(P.string(" to "), P.unsigned())
+move_parser = P.seq(amount_parser, from_parser, to_parser)
+
+
+@dataclass(slots=True)
+class State:
+    crates: list[str]
+    moves: list[tuple[int, int, int]]
+
+    @staticmethod
+    def parse_crate_line(line: str) -> list[None | str] | None:
+        return crate_row_parser.parse(line).get_or(None)
+
+    @staticmethod
+    def parse_drawing(lines: Iterator[str]) -> list[str]:
+        result: list[str] = []
+        for line in lines:
+            crates = State.parse_crate_line(line)
+            if crates is None:
+                return result
+
+            if len(result) < len(crates):
+                result += [""] * (len(crates) - len(result))
+            for stack, crate in enumerate(crates):
+                if crate is not None:
+                    result[stack] = crate + result[stack]
+
+        raise Exception("Can never happen")
+
+    @staticmethod
+    def parse_move(line: str) -> tuple[int, int, int]:
+        amount, frm, to = move_parser.parse(line).get()
+        return amount, frm - 1, to - 1
+
+    @staticmethod
+    def parse(lines: Iterator[str]) -> State:
+        drawing = State.parse_drawing(lines)
+        next(lines)
+        moves = [State.parse_move(line) for line in lines]
+        return State(drawing, moves)
+
+    @staticmethod
+    def do_move9000(crates: list[str], move: tuple[int, int, int]) -> list[str]:
+        """
+        Moves the given crates by the provided move. Will fail if there are not enough crates
+        in the from stack
+        """
+        for _ in range(move[0]):
+            crates[move[2]] += crates[move[1]][-1]
+            crates[move[1]] = crates[move[1]][:-1]
+
+        return crates
+
+    def all_moves9000(self) -> list[str]:
+        crates = self.crates
+        for move in self.moves:
+            crates = State.do_move9000(crates, move)
+        return crates
+
+    @staticmethod
+    def do_move9001(crates: list[str], move: tuple[int, int, int]) -> list[str]:
+        """
+        Moves the given crates by the provided move. Will fail if there are not enough crates
+        in the from stack
+        """
+        crates[move[2]] += crates[move[1]][-move[0]:]
+        crates[move[1]] = crates[move[1]][:-move[0]]
+        return crates
+
+    def all_moves9001(self) -> list[str]:
+        crates = self.crates
+        for move in self.moves:
+            crates = State.do_move9001(crates, move)
+        return crates
+
+    @staticmethod
+    def top(crates: list[str]) -> str:
+        """ Lists the last item in the given stacks. Fails if any stack is empty """
+        return ''.join(stack[-1] for stack in crates)