AoC 2024 day 13 part 1

aoc2024/src/day13/python/solution.py

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+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import re
+import math
+from typing import Sequence
+
+type Vector = tuple[int, int]
+type Machine = tuple[Vector, ...]
+_BUTTON_A_COST = 3  # Tokens
+_BUTTON_B_COST = 1  # Token
+# Buttons will not be pressed more than 100 times.
+_MAX_BUTTON_PRESSES = 100
+
+
+def _parse(input: Sequence[str]) -> tuple[Machine, ...]:
+  part = 0
+  machines = []
+  machine = []
+  for i in range(len(input)):
+    if part == 0 and input[i] != '':
+      a_matches = re.match(r'Button A: X\+(\d+), Y\+(\d+)', input[i])
+      machine.append((int(a_matches[1]), int(a_matches[2])))
+      part = 1
+    elif part == 1:
+      b_matches = re.match(r'Button B: X\+(\d+), Y\+(\d+)', input[i])
+      machine.append((int(b_matches[1]), int(b_matches[2])))
+      part = 2
+    elif part == 2:
+      price_matches = re.match(r'Prize: X=(\d+), Y=(\d+)', input[i])
+      machine.append((int(price_matches[1]), int(price_matches[2])))
+      machines.append(tuple(machine))
+      machine = []
+      part = 0
+  return tuple(machines)
+
+
+def _calc_tokens_brute_force(vector_0: Vector, vector_1: Vector, vector_2: Vector) -> int | None:
+  min_tokens = math.inf
+  for a in range(1, _MAX_BUTTON_PRESSES):
+    for b in range(1, _MAX_BUTTON_PRESSES):
+      if a * vector_0[0] + b * vector_1[0] == vector_2[0] and a * vector_0[1] + b * vector_1[1] == vector_2[1]:
+        tokens = a * _BUTTON_A_COST + b * _BUTTON_B_COST
+        if tokens < min_tokens:
+          min_tokens = tokens
+  return min_tokens if min_tokens < math.inf else None
+
+
+def min_tokens_to_win(input: Sequence[str]) -> int | None:
+  claw_machines = _parse(input)
+  num_tokens = 0
+  for machine in claw_machines:
+    tokens = _calc_tokens_brute_force(machine[0], machine[1], machine[2])
+    if tokens is not None:
+      num_tokens += tokens
+  return num_tokens if num_tokens > 0 else None

aoc2024/test/day13/python/example1.txt

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+Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400

aoc2024/test/day13/python/example2.txt

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+Button A: X+26, Y+66
+Button B: X+67, Y+21
+Prize: X=12748, Y=12176

aoc2024/test/day13/python/example3.txt

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+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450

aoc2024/test/day13/python/example4.txt

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+Button A: X+69, Y+23
+Button B: X+27, Y+71
+Prize: X=18641, Y=10279

aoc2024/test/day13/python/example5.txt

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+Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400
+
+Button A: X+26, Y+66
+Button B: X+67, Y+21
+Prize: X=12748, Y=12176
+
+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450
+
+Button A: X+69, Y+23
+Button B: X+27, Y+71
+Prize: X=18641, Y=10279