2015 day 21.

.gitignore

@@ -1 +1,2 @@
 venv
+__pycache__

2021/day9.py

@@ -1,13 +0,0 @@
-import sys
-from collections import defaultdict
-from dataclasses import dataclass
-
-lines = sys.stdin.read().splitlines()
-
-# part 1
-answer_1 = ...
-print(f"answer 1 is {answer_1}")
-
-# part 2
-answer_2 = ...
-print(f"answer 2 is {answer_2}")

2023/day20.py

@@ -1,13 +0,0 @@
-import sys
-from collections import defaultdict
-from dataclasses import dataclass
-
-lines = sys.stdin.read().splitlines()
-
-# part 1
-answer_1 = ...
-print(f"answer 1 is {answer_1}")
-
-# part 2
-answer_2 = ...
-print(f"answer 2 is {answer_2}")

2023/day21.py

@@ -1,13 +0,0 @@
-import sys
-from collections import defaultdict
-from dataclasses import dataclass
-
-lines = sys.stdin.read().splitlines()
-
-# part 1
-answer_1 = ...
-print(f"answer 1 is {answer_1}")
-
-# part 2
-answer_2 = ...
-print(f"answer 2 is {answer_2}")

2023/day22.py

@@ -1,13 +0,0 @@
-import sys
-from collections import defaultdict
-from dataclasses import dataclass
-
-lines = sys.stdin.read().splitlines()
-
-# part 1
-answer_1 = ...
-print(f"answer 1 is {answer_1}")
-
-# part 2
-answer_2 = ...
-print(f"answer 2 is {answer_2}")

2023/day23.py

@@ -1,13 +0,0 @@
-import sys
-from collections import defaultdict
-from dataclasses import dataclass
-
-lines = sys.stdin.read().splitlines()
-
-# part 1
-answer_1 = ...
-print(f"answer 1 is {answer_1}")
-
-# part 2
-answer_2 = ...
-print(f"answer 2 is {answer_2}")

2023/day24.py

@@ -1,13 +0,0 @@
-import sys
-from collections import defaultdict
-from dataclasses import dataclass
-
-lines = sys.stdin.read().splitlines()
-
-# part 1
-answer_1 = ...
-print(f"answer 1 is {answer_1}")
-
-# part 2
-answer_2 = ...
-print(f"answer 2 is {answer_2}")

2023/day25.py

@@ -1,13 +0,0 @@
-import sys
-from collections import defaultdict
-from dataclasses import dataclass
-
-lines = sys.stdin.read().splitlines()
-
-# part 1
-answer_1 = ...
-print(f"answer 1 is {answer_1}")
-
-# part 2
-answer_2 = ...
-print(f"answer 2 is {answer_2}")

README.md

@@ -1,7 +1,36 @@
-# Advent Of Code
+# Holt59 - Advent Of Code
 
-To run any script, you need to pipe the input:
+Installation (with [`poetry`](https://python-poetry.org/)):
 
 ```bash
-cat 2022/inputs/day2.txt | python 2022/day2.py
+poetry install
+```
+
+To run any day:
+
+```bash
+holt59-aoc $day
+```
+
+You can use `-v` / `--verbose` for extra outputs in some case, `-t` / `--test` to run
+the code on the test data (one of the test data if multiple are present) or even
+`-u XXX` / `--user XXX` to run the code on a specific input after putting the input
+file under `src/holt59/aoc/inputs/XXX/$year/$day`.
+
+Full usage:
+
+```bash
+usage: Holt59 Advent-Of-Code Runner [-h] [-v] [-t] [-u USER] [-i INPUT] [-y YEAR] day
+
+positional arguments:
+  day                   day to run
+
+options:
+  -h, --help            show this help message and exit
+  -v, --verbose         verbose mode
+  -t, --test            test mode
+  -u USER, --user USER  user input to use
+  -i INPUT, --input INPUT
+                        input to use (override user and test)
+  -y YEAR, --year YEAR  year to run
 ```

pyproject.toml

@@ -0,0 +1,52 @@
+[tool.poetry]
+name = "holt59-advent-of-code"
+version = "0.1.0"
+description = ""
+authors = ["Mikael CAPELLE <capelle.mikael@gmail.com>"]
+license = "MIT"
+readme = "README.md"
+packages = [{ include = "holt59", from = "src" }]
+
+[tool.poetry.dependencies]
+python = "^3.10"
+numpy = "^1.26.2"
+tqdm = "^4.66.1"
+parse = "^1.20.0"
+scipy = "^1.11.4"
+ortools = "^9.8.3296"
+sympy = "^1.12"
+networkx = "^3.2.1"
+
+[tool.poetry.scripts]
+holt59-aoc = "holt59.aoc.__main__:main"
+
+[tool.poe.tasks]
+lint-black = "black --check --diff src tests typings"
+lint-isort = "isort -c src tests typings"
+lint-ruff = "ruff src tests typings"
+lint-flake8 = "flake8 src tests typings"
+lint-pyright = "pyright src tests"
+lint-all.sequence = [
+    "lint-black",
+    "lint-isort",
+    "lint-flake8",
+    "lint-ruff",
+    "lint-pyright",
+]
+lint-all.ignore_fail = "return_non_zero"
+
+[tool.poetry.group.dev.dependencies]
+flake8 = "^6.1.0"
+flake8-black = "^0.3.6"
+black = "^23.12.0"
+pyright = "^1.1.341"
+mypy = "^1.7.1"
+isort = "^5.13.2"
+ruff = "^0.1.8"
+poethepoet = "^0.24.4"
+ipykernel = "^6.27.1"
+networkx-stubs = "^0.0.1"
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"

src/holt59/aoc/2015/day1.py

@@ -0,0 +1,10 @@
+import sys
+
+line = sys.stdin.read().strip()
+
+floor = 0
+floors = [(floor := floor + (1 if c == "(" else -1)) for c in line]
+
+
+print(f"answer 1 is {floors[-1]}")
+print(f"answer 2 is {floors.index(-1)}")

src/holt59/aoc/2015/day10.py

@@ -0,0 +1,148 @@
+import itertools
+import sys
+
+line = sys.stdin.read().strip()
+
+# see http://www.se16.info/js/lands2.htm for the explanation of 'atoms' (or elements)
+#
+# see also https://www.youtube.com/watch?v=ea7lJkEhytA (video link from AOC) and this
+# CodeGolf answer https://codegolf.stackexchange.com/a/8479/42148
+
+# fmt: off
+atoms = [
+    ("22", (0, )),  # 0
+    ("13112221133211322112211213322112", (71, 90, 0, 19, 2, )),  # 1
+    ("312211322212221121123222112", (1, )),  # 2
+    ("111312211312113221133211322112211213322112", (31, 19, 2, )),  # 3
+    ("1321132122211322212221121123222112", (3, )),  # 4
+    ("3113112211322112211213322112", (4, )),  # 5
+    ("111312212221121123222112", (5, )),  # 6
+    ("132112211213322112", (6, )),  # 7
+    ("31121123222112", (7, )),  # 8
+    ("111213322112", (8, )),  # 9
+    ("123222112", (9, )),  # 10
+    ("3113322112", (60, 10, )),  # 11
+    ("1113222112", (11, )),  # 12
+    ("1322112", (12, )),  # 13
+    ("311311222112", (66, 13, )),  # 14
+    ("1113122112", (14, )),  # 15
+    ("132112", (15, )),  # 16
+    ("3112", (16, )),  # 17
+    ("1112", (17, )),  # 18
+    ("12", (18, )),  # 19
+    ("3113112221133112", (66, 90, 0, 19, 26, )),  # 20
+    ("11131221131112", (20, )),  # 21
+    ("13211312", (21, )),  # 22
+    ("31132", (22, )),  # 23
+    ("111311222112", (23, 13, )),  # 24
+    ("13122112", (24, )),  # 25
+    ("32112", (25, )),  # 26
+    ("11133112", (29, 26, )),  # 27
+    ("131112", (27, )),  # 28
+    ("312", (28, )),  # 29
+    ("13221133122211332", (62, 19, 88, 0, 19, 29, )),  # 30
+    ("31131122211311122113222", (66, 30, )),  # 31
+    ("11131221131211322113322112", (31, 10, )),  # 32
+    ("13211321222113222112", (32, )),  # 33
+    ("3113112211322112", (33, )),  # 34
+    ("11131221222112", (34, )),  # 35
+    ("1321122112", (35, )),  # 36
+    ("3112112", (36, )),  # 37
+    ("1112133", (37, 91, )),  # 38
+    ("12322211331222113112211", (38, 0, 19, 42, )),  # 39
+    ("1113122113322113111221131221", (67, 39, )),  # 40
+    ("13211322211312113211", (40, )),  # 41
+    ("311322113212221", (41, )),  # 42
+    ("132211331222113112211", (62, 19, 42, )),  # 43
+    ("311311222113111221131221", (66, 43, )),  # 44
+    ("111312211312113211", (44, )),  # 45
+    ("132113212221", (45, )),  # 46
+    ("3113112211", (46, )),  # 47
+    ("11131221", (47, )),  # 48
+    ("13211", (48, )),  # 49
+    ("3112221", (60, 49, )),  # 50
+    ("1322113312211", (62, 19, 50, )),  # 51
+    ("311311222113111221", (66, 51, )),  # 52
+    ("11131221131211", (52, )),  # 53
+    ("13211321", (53, )),  # 54
+    ("311311", (54, )),  # 55
+    ("11131", (55, )),  # 56
+    ("1321133112", (56, 0, 19, 26, )),  # 57
+    ("31131112", (57, )),  # 58
+    ("111312", (58, )),  # 59
+    ("132", (59, )),  # 60
+    ("311332", (60, 19, 29, )),  # 61
+    ("1113222", (61, )),  # 62
+    ("13221133112", (62, 19, 26, )),  # 63
+    ("3113112221131112", (66, 63, )),  # 64
+    ("111312211312", (64, )),  # 65
+    ("1321132", (65, )),  # 66
+    ("311311222", (66, 60, )),  # 67
+    ("11131221133112", (67, 19, 26, )),  # 68
+    ("1321131112", (68, )),  # 69
+    ("311312", (69, )),  # 70
+    ("11132", (70, )),  # 71
+    ("13112221133211322112211213322113", (71, 90, 0, 19, 73, )),  # 72
+    ("312211322212221121123222113", (72, )),  # 73
+    ("111312211312113221133211322112211213322113", (31, 19, 73, )),  # 74
+    ("1321132122211322212221121123222113", (74, )),  # 75
+    ("3113112211322112211213322113", (75, )),  # 76
+    ("111312212221121123222113", (76, )),  # 77
+    ("132112211213322113", (77, )),  # 78
+    ("31121123222113", (78, )),  # 79
+    ("111213322113", (79, )),  # 80
+    ("123222113", (80, )),  # 81
+    ("3113322113", (60, 81, )),  # 82
+    ("1113222113", (82, )),  # 83
+    ("1322113", (83, )),  # 84
+    ("311311222113", (66, 84, )),  # 85
+    ("1113122113", (85, )),  # 86
+    ("132113", (86, )),  # 87
+    ("3113", (87, )),  # 88
+    ("1113", (88, )),  # 89
+    ("13", (89, )),  # 90
+    ("3", (90, )),  # 91
+]
+# fmt: on
+
+starters = [
+    "1",
+    "11",
+    "21",
+    "1211",
+    "111221",
+    "312211",
+    "13112221",
+    "1113213211",
+    "31131211131221",
+]
+
+
+def look_and_say_length(s: str, n: int) -> int:
+    if n == 0:
+        return len(s)
+
+    if s in starters:
+        return look_and_say_length(
+            "".join(f"{len(list(g))}{k}" for k, g in itertools.groupby(s)), n - 1
+        )
+
+    counts = {i: 0 for i in range(len(atoms))}
+    idx = next(i for i, (a, _) in enumerate(atoms) if s == a)
+    counts[idx] = 1
+
+    for _ in range(n):
+        c2 = {i: 0 for i in range(len(atoms))}
+        for i in counts:
+            for j in atoms[i][1]:
+                c2[j] += counts[i]
+        counts = c2
+
+    return sum(counts[i] * len(a[0]) for i, a in enumerate(atoms))
+
+
+answer_1 = look_and_say_length(line, 40)
+print(f"answer 1 is {answer_1}")
+
+answer_2 = look_and_say_length(line, 50)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day11.py

@@ -0,0 +1,49 @@
+import itertools
+import sys
+
+
+def is_valid(p: str) -> bool:
+    if any(c in "iol" for c in p):
+        return False
+
+    if not any(
+        ord(a) + 1 == ord(b) and ord(b) + 1 == ord(c)
+        for a, b, c in zip(p, p[1:], p[2:])
+    ):
+        return False
+
+    if sum(len(list(g)) >= 2 for _, g in itertools.groupby(p)) < 2:
+        return False
+
+    return True
+
+
+assert not is_valid("hijklmmn")
+assert not is_valid("abbceffg")
+assert not is_valid("abbcegjk")
+assert is_valid("abcdffaa")
+assert is_valid("ghjaabcc")
+
+
+def increment(p: str) -> str:
+    if p[-1] == "z":
+        return increment(p[:-1]) + "a"
+    elif p[-1] in "iol":
+        return p[:-1] + chr(ord(p[-1]) + 2)
+    else:
+        return p[:-1] + chr(ord(p[-1]) + 1)
+
+
+def find_next_password(p: str) -> str:
+    while not is_valid(p):
+        p = increment(p)
+    return p
+
+
+line = sys.stdin.read().strip()
+
+answer_1 = find_next_password(line)
+print(f"answer 1 is {answer_1}")
+
+answer_2 = find_next_password(increment(answer_1))
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day12.py

@@ -0,0 +1,27 @@
+import json
+import sys
+from typing import TypeAlias
+
+JsonObject: TypeAlias = dict[str, "JsonObject"] | list["JsonObject"] | int | str
+
+
+def json_sum(value: JsonObject, ignore: str | None = None) -> int:
+    if isinstance(value, str):
+        return 0
+    elif isinstance(value, int):
+        return value
+    elif isinstance(value, list):
+        return sum(json_sum(v, ignore=ignore) for v in value)
+    elif ignore not in value.values():
+        return sum(json_sum(v, ignore=ignore) for v in value.values())
+    else:
+        return 0
+
+
+data: JsonObject = json.load(sys.stdin)
+
+answer_1 = json_sum(data)
+print(f"answer 1 is {answer_1}")
+
+answer_2 = json_sum(data, "red")
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day13.py

@@ -0,0 +1,41 @@
+import itertools
+import sys
+from collections import defaultdict
+from typing import Literal, cast
+
+import parse  # type: ignore
+
+
+def max_change_in_happiness(happiness: dict[str, dict[str, int]]) -> int:
+    guests = list(happiness)
+    return max(
+        sum(
+            happiness[o][d] + happiness[d][o]
+            for o, d in zip((guests[0],) + order, order + (guests[0],))
+        )
+        for order in map(tuple, itertools.permutations(guests[1:]))
+    )
+
+
+lines = sys.stdin.read().splitlines()
+
+happiness: dict[str, dict[str, int]] = defaultdict(dict)
+for line in lines:
+    u1, gain_or_loose, hap, u2 = cast(
+        tuple[str, Literal["gain", "lose"], int, str],
+        parse.parse(  # type: ignore
+            "{} would {} {:d} happiness units by sitting next to {}.", line
+        ),
+    )
+    happiness[u1][u2] = hap if gain_or_loose == "gain" else -hap
+
+
+answer_1 = max_change_in_happiness(happiness)
+print(f"answer 1 is {answer_1}")
+
+for guest in list(happiness):
+    happiness["me"][guest] = 0
+    happiness[guest]["me"] = 0
+
+answer_2 = max_change_in_happiness(happiness)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day14.py

@@ -0,0 +1,62 @@
+import sys
+from dataclasses import dataclass
+from typing import Literal, cast
+
+import parse  # type: ignore
+
+
+@dataclass(frozen=True)
+class Reindeer:
+    name: str
+    speed: int
+    fly_time: int
+    rest_time: int
+
+
+lines = sys.stdin.read().splitlines()
+
+reindeers: list[Reindeer] = []
+for line in lines:
+    reindeer, speed, speed_time, rest_time = cast(
+        tuple[str, int, int, int],
+        parse.parse(  # type: ignore
+            "{} can fly {:d} km/s for {:d} seconds, "
+            "but then must rest for {:d} seconds.",
+            line,
+        ),
+    )
+    reindeers.append(
+        Reindeer(name=reindeer, speed=speed, fly_time=speed_time, rest_time=rest_time)
+    )
+
+target = 1000 if len(reindeers) <= 2 else 2503
+
+states: dict[Reindeer, tuple[Literal["resting", "flying"], int]] = {
+    reindeer: ("resting", 0) for reindeer in reindeers
+}
+distances: dict[Reindeer, int] = {reindeer: 0 for reindeer in reindeers}
+points: dict[Reindeer, int] = {reindeer: 0 for reindeer in reindeers}
+
+for time in range(target):
+    for reindeer in reindeers:
+        if states[reindeer][0] == "flying":
+            distances[reindeer] += reindeer.speed
+
+    top_distance = max(distances.values())
+    for reindeer in reindeers:
+        if distances[reindeer] == top_distance:
+            points[reindeer] += 1
+
+    for reindeer in reindeers:
+        if states[reindeer][1] == time:
+            if states[reindeer][0] == "resting":
+                states[reindeer] = ("flying", time + reindeer.fly_time)
+            else:
+                states[reindeer] = ("resting", time + reindeer.rest_time)
+
+
+answer_1 = max(distances.values())
+print(f"answer 1 is {answer_1}")
+
+answer_2 = max(points.values()) - 1
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day15.py

@@ -0,0 +1,57 @@
+import math
+import sys
+from typing import Sequence, cast
+
+import parse  # type: ignore
+
+
+def score(ingredients: list[list[int]], teaspoons: Sequence[int]) -> int:
+    return math.prod(
+        max(
+            0,
+            sum(
+                ingredient[prop] * teaspoon
+                for ingredient, teaspoon in zip(ingredients, teaspoons)
+            ),
+        )
+        for prop in range(len(ingredients[0]) - 1)
+    )
+
+
+lines = sys.stdin.read().splitlines()
+
+ingredients: list[list[int]] = []
+for line in lines:
+    _, *scores = cast(
+        tuple[str, int, int, int, int, int],
+        parse.parse(  # type: ignore
+            "{}: capacity {:d}, durability {:d}, flavor {:d}, "
+            "texture {:d}, calories {:d}",
+            line,
+        ),
+    )
+    ingredients.append(scores)
+
+total_teaspoons = 100
+calories: list[int] = []
+scores: list[int] = []
+
+for a in range(total_teaspoons + 1):
+    for b in range(total_teaspoons + 1 - a):
+        for c in range(total_teaspoons + 1 - a - b):
+            teaspoons = (a, b, c, total_teaspoons - a - b - c)
+
+            scores.append(score(ingredients, teaspoons))
+            calories.append(
+                sum(
+                    ingredient[-1] * teaspoon
+                    for ingredient, teaspoon in zip(ingredients, teaspoons)
+                )
+            )
+
+
+answer_1 = max(scores)
+print(f"answer 1 is {answer_1}")
+
+answer_2 = max(score for score, calory in zip(scores, calories) if calory == 500)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day16.py

@@ -0,0 +1,51 @@
+import operator as op
+import re
+import sys
+from collections import defaultdict
+from typing import Callable
+
+MFCSAM: dict[str, int] = {
+    "children": 3,
+    "cats": 7,
+    "samoyeds": 2,
+    "pomeranians": 3,
+    "akitas": 0,
+    "vizslas": 0,
+    "goldfish": 5,
+    "trees": 3,
+    "cars": 2,
+    "perfumes": 1,
+}
+
+lines = sys.stdin.readlines()
+
+aunts: list[dict[str, int]] = [
+    {
+        match[1]: int(match[2])
+        for match in re.findall(R"((?P<compound>[^:, ]+): (?P<quantity>\d+))", line)
+    }
+    for line in lines
+]
+
+
+def match(operators: dict[str, Callable[[int, int], bool]]) -> int:
+    return next(
+        i
+        for i, aunt in enumerate(aunts, start=1)
+        if all(operators[k](aunt[k], MFCSAM[k]) for k in aunt)
+    )
+
+
+answer_1 = match(defaultdict(lambda: op.eq))
+print(f"answer 1 is {answer_1}")
+
+answer_2 = match(
+    defaultdict(
+        lambda: op.eq,
+        trees=op.gt,
+        cats=op.gt,
+        pomeranians=op.lt,
+        goldfish=op.lt,
+    )
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day17.py

@@ -0,0 +1,30 @@
+import sys
+from typing import Iterator
+
+
+def iter_combinations(value: int, containers: list[int]) -> Iterator[tuple[int, ...]]:
+    if value < 0:
+        return
+
+    if value == 0:
+        yield ()
+
+    for i in range(len(containers)):
+        for combination in iter_combinations(
+            value - containers[i], containers[i + 1 :]
+        ):
+            yield (containers[i],) + combination
+
+
+containers = [int(c) for c in sys.stdin.read().split()]
+total = 25 if len(containers) <= 5 else 150
+
+combinations = [combination for combination in iter_combinations(total, containers)]
+
+answer_1 = len(combinations)
+print(f"answer 1 is {answer_1}")
+
+min_containers = min(len(combination) for combination in combinations)
+
+answer_2 = sum(1 for combination in combinations if len(combination) == min_containers)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day18.py

@@ -0,0 +1,66 @@
+import itertools
+import sys
+
+import numpy as np
+from numpy.typing import NDArray
+
+grid0 = np.array([[c == "#" for c in line] for line in sys.stdin.read().splitlines()])
+
+# add an always off circle around
+grid0 = np.concatenate(
+    [
+        np.zeros((grid0.shape[0] + 2, 1), dtype=bool),
+        np.concatenate(
+            [
+                np.zeros((1, grid0.shape[1]), dtype=bool),
+                grid0,
+                np.zeros((1, grid0.shape[1]), dtype=bool),
+            ]
+        ),
+        np.zeros((grid0.shape[0] + 2, 1), dtype=bool),
+    ],
+    axis=1,
+)
+
+moves = list(itertools.product([-1, 0, 1], repeat=2))
+moves.remove((0, 0))
+
+jjs, iis = np.meshgrid(
+    np.arange(1, grid0.shape[0] - 1, dtype=int),
+    np.arange(1, grid0.shape[1] - 1, dtype=int),
+)
+iis, jjs = iis.flatten(), jjs.flatten()
+
+ins = iis[:, None] + np.array(moves)[:, 0]
+jns = jjs[:, None] + np.array(moves)[:, 1]
+
+
+def game_of_life(grid: NDArray[np.bool_]) -> NDArray[np.bool_]:
+    neighbors_on = grid[ins, jns].sum(axis=1)
+    cells_on = grid[iis, jjs]
+
+    grid = np.zeros_like(grid)
+    grid[iis, jjs] = (neighbors_on == 3) | (cells_on & (neighbors_on == 2))
+
+    return grid
+
+
+grid = grid0
+n_steps = 4 if len(grid) < 10 else 100
+for _ in range(n_steps):
+    grid = game_of_life(grid)
+
+answer_1 = grid.sum()
+print(f"answer 1 is {answer_1}")
+
+
+n_steps = 5 if len(grid) < 10 else 100
+grid = grid0
+for _ in range(n_steps):
+    grid[[1, 1, -2, -2], [1, -2, 1, -2]] = True
+    grid = game_of_life(grid)
+
+grid[[1, 1, -2, -2], [1, -2, 1, -2]] = True
+
+answer_2 = sum(cell for line in grid for cell in line)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day19.py

@@ -0,0 +1,56 @@
+import sys
+from collections import defaultdict
+
+replacements_s, molecule = sys.stdin.read().split("\n\n")
+
+REPLACEMENTS: dict[str, list[str]] = defaultdict(list)
+for replacement_s in replacements_s.splitlines():
+    p = replacement_s.split(" => ")
+    REPLACEMENTS[p[0]].append(p[1])
+molecule = molecule.strip()
+
+generated = [
+    molecule[:i] + replacement + molecule[i + len(symbol) :]
+    for symbol, replacements in REPLACEMENTS.items()
+    for replacement in replacements
+    for i in range(len(molecule))
+    if molecule[i:].startswith(symbol)
+]
+
+answer_1 = len(set(generated))
+print(f"answer 1 is {answer_1}")
+
+inversion: dict[str, str] = {
+    replacement: symbol
+    for symbol, replacements in REPLACEMENTS.items()
+    for replacement in replacements
+}
+
+# there is actually only one way to create the molecule, and we can greedily replace
+# tokens with their replacements, e.g., if H => OH then we can replace OH by H directly
+# without thinking
+
+count = 0
+while molecule != "e":
+    i = 0
+    m2 = ""
+    while i < len(molecule):
+        found = False
+        for replacement in inversion:
+            if molecule[i:].startswith(replacement):
+                m2 += inversion[replacement]
+                i += len(replacement)
+                count += 1
+                found = True
+                break
+
+        if not found:
+            m2 += molecule[i]
+            i += 1
+
+    # print(m2)
+    molecule = m2
+
+
+answer_2 = count
+print(f"answer 2 is {count}")

src/holt59/aoc/2015/day2.py

@@ -0,0 +1,20 @@
+import sys
+
+import numpy as np
+
+lines = sys.stdin.read().splitlines()
+
+length, width, height = np.array(
+    [[int(c) for c in line.split("x")] for line in lines]
+).T
+
+lw, wh, hl = (length * width, width * height, height * length)
+
+answer_1 = np.sum(2 * (lw + wh + hl) + np.min(np.stack([lw, wh, hl]), axis=0))
+print(f"answer 1 is {answer_1}")
+
+answer_2 = np.sum(
+    length * width * height
+    + 2 * np.min(np.stack([length + width, length + height, height + width]), axis=0)
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day20.py

@@ -0,0 +1,28 @@
+import itertools
+import sys
+
+target = int(sys.stdin.read())
+
+
+def presents(n: int, elf: int, max: int = target) -> int:
+    count = 0
+    k = 1
+    while k * k < n:
+        if n % k == 0:
+            if n // k <= max:
+                count += elf * k
+            if k <= max:
+                count += elf * (n // k)
+        k += 1
+
+    if k * k == n and k <= max:
+        count += elf * k
+
+    return count
+
+
+answer_1 = next(n for n in itertools.count(1) if presents(n, 10) >= target)
+print(f"answer 1 is {answer_1}")
+
+answer_2 = next(n for n in itertools.count(1) if presents(n, 11, 50) >= target)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day21.py

@@ -0,0 +1,66 @@
+import itertools
+import sys
+from math import ceil
+from typing import TypeAlias
+
+Modifier: TypeAlias = tuple[str, int, int, int]
+
+WEAPONS: list[Modifier] = [
+    ("Dagger", 8, 4, 0),
+    ("Shortsword", 10, 5, 0),
+    ("Warhammer", 25, 6, 0),
+    ("Longsword", 40, 7, 0),
+    ("Greataxe", 74, 8, 0),
+]
+
+ARMORS: list[Modifier] = [
+    ("", 0, 0, 0),
+    ("Leather", 13, 0, 1),
+    ("Chainmail", 31, 0, 2),
+    ("Splintmail", 53, 0, 3),
+    ("Bandedmail", 75, 0, 4),
+    ("Platemail", 102, 0, 5),
+]
+
+RINGS: list[Modifier] = [
+    ("", 0, 0, 0),
+    ("Damage +1", 25, 1, 0),
+    ("Damage +2", 50, 2, 0),
+    ("Damage +3", 100, 3, 0),
+    ("Defense +1", 20, 0, 1),
+    ("Defense +2", 40, 0, 2),
+    ("Defense +3", 80, 0, 3),
+]
+
+
+lines = sys.stdin.read().splitlines()
+
+player_hp = 100
+
+boss_attack = int(lines[1].split(":")[1].strip())
+boss_armor = int(lines[2].split(":")[1].strip())
+boss_hp = int(lines[0].split(":")[1].strip())
+
+
+min_cost, max_cost = 1_000_000, 0
+for equipments in itertools.product(WEAPONS, ARMORS, RINGS, RINGS):
+    if equipments[-1][0] != "" and equipments[-2] == equipments[-1]:
+        continue
+
+    cost, player_attack, player_armor = (
+        sum(equipment[1:][k] for equipment in equipments) for k in range(3)
+    )
+
+    if ceil(boss_hp / max(1, player_attack - boss_armor)) <= ceil(
+        player_hp / max(1, boss_attack - player_armor)
+    ):
+        min_cost = min(cost, min_cost)
+    else:
+        max_cost = max(cost, max_cost)
+
+
+answer_1 = min_cost
+print(f"answer 1 is {answer_1}")
+
+answer_2 = max_cost
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day3.py

@@ -0,0 +1,34 @@
+import sys
+from collections import defaultdict
+
+line = sys.stdin.read().strip()
+
+
+def process(directions: str) -> dict[tuple[int, int], int]:
+    counts: dict[tuple[int, int], int] = defaultdict(lambda: 0)
+    counts[0, 0] = 1
+    x, y = (0, 0)
+
+    for c in directions:
+        match c:
+            case ">":
+                x += 1
+            case "<":
+                x -= 1
+            case "^":
+                y -= 1
+            case "v":
+                y += 1
+            case _:
+                raise ValueError()
+
+        counts[x, y] += 1
+
+    return counts
+
+
+answer_1 = len(process(line))
+print(f"answer 1 is {answer_1}")
+
+answer_2 = len(process(line[::2]) | process(line[1::2]))
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day4.py

@@ -0,0 +1,16 @@
+import hashlib
+import itertools
+import sys
+
+line = sys.stdin.read().strip()
+
+it = iter(itertools.count(1))
+answer_1 = next(
+    i for i in it if hashlib.md5(f"{line}{i}".encode()).hexdigest().startswith("00000")
+)
+print(f"answer 1 is {answer_1}")
+
+answer_2 = next(
+    i for i in it if hashlib.md5(f"{line}{i}".encode()).hexdigest().startswith("000000")
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day5.py

@@ -0,0 +1,36 @@
+import sys
+
+VOWELS = "aeiou"
+FORBIDDEN = {"ab", "cd", "pq", "xy"}
+
+
+def is_nice_1(s: str) -> bool:
+    if sum(c in VOWELS for c in s) < 3:
+        return False
+
+    if not any(a == b for a, b in zip(s[:-1:], s[1::])):
+        return False
+
+    if any(s.find(f) >= 0 for f in FORBIDDEN):
+        return False
+
+    return True
+
+
+def is_nice_2(s: str) -> bool:
+    if not any(s.find(s[i : i + 2], i + 2) >= 0 for i in range(len(s))):
+        return False
+
+    if not any(a == b for a, b in zip(s[:-1:], s[2::])):
+        return False
+
+    return True
+
+
+lines = sys.stdin.read().splitlines()
+
+answer_1 = sum(map(is_nice_1, lines))
+print(f"answer 1 is {answer_1}")
+
+answer_2 = sum(map(is_nice_2, lines))
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day6.py

@@ -0,0 +1,33 @@
+import sys
+from typing import Literal, cast
+
+import numpy as np
+import parse  # type: ignore
+
+lines = sys.stdin.read().splitlines()
+
+lights_1 = np.zeros((1000, 1000), dtype=bool)
+lights_2 = np.zeros((1000, 1000), dtype=int)
+for line in lines:
+    action, sx, sy, ex, ey = cast(
+        tuple[Literal["turn on", "turn off", "toggle"], int, int, int, int],
+        parse.parse("{} {:d},{:d} through {:d},{:d}", line),  # type: ignore
+    )
+    ex, ey = ex + 1, ey + 1
+
+    match action:
+        case "turn on":
+            lights_1[sx:ex, sy:ey] = True
+            lights_2[sx:ex, sy:ey] += 1
+        case "turn off":
+            lights_1[sx:ex, sy:ey] = False
+            lights_2[sx:ex, sy:ey] = np.maximum(lights_2[sx:ex, sy:ey] - 1, 0)
+        case "toggle":
+            lights_1[sx:ex, sy:ey] = ~lights_1[sx:ex, sy:ey]
+            lights_2[sx:ex, sy:ey] += 2
+
+answer_1 = lights_1.sum()
+print(f"answer 1 is {answer_1}")
+
+answer_2 = lights_2.sum()
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day7.py

@@ -0,0 +1,101 @@
+import logging
+import operator
+import os
+import sys
+from typing import Callable
+
+VERBOSE = os.getenv("AOC_VERBOSE") == "True"
+logging.basicConfig(level=logging.INFO if VERBOSE else logging.WARNING)
+
+OPERATORS = {
+    "AND": operator.and_,
+    "OR": operator.or_,
+    "LSHIFT": operator.lshift,
+    "RSHIFT": operator.rshift,
+}
+
+ValueGetter = Callable[[dict[str, int]], int]
+Signals = dict[
+    str,
+    tuple[
+        tuple[str, str],
+        tuple[ValueGetter, ValueGetter],
+        Callable[[int, int], int],
+    ],
+]
+
+
+def zero_op(_a: int, _b: int) -> int:
+    return 0
+
+
+def value_of(key: str) -> tuple[str, Callable[[dict[str, int]], int]]:
+    try:
+        return "", lambda _p, _v=int(key): _v
+    except ValueError:
+        return key, lambda values: values[key]
+
+
+lines = sys.stdin.read().splitlines()
+
+signals: Signals = {}
+values: dict[str, int] = {"": 0}
+
+for line in lines:
+    command, signal = line.split(" -> ")
+
+    if command.startswith("NOT"):
+        name = command.split(" ")[1]
+        signals[signal] = (
+            (name, ""),
+            (lambda values, _n=name: values[_n], lambda _v: 0),
+            lambda a, _b: ~a,
+        )
+
+    elif not any(command.find(name) >= 0 for name in OPERATORS):
+        try:
+            values[signal] = int(command)
+        except ValueError:
+            signals[signal] = (
+                (command, ""),
+                (lambda values, _c=command: values[_c], lambda _v: 0),
+                lambda a, _b: a,
+            )
+
+    else:
+        op: Callable[[int, int], int] = zero_op
+        lhs_s, rhs_s = "", ""
+
+        for name in OPERATORS:
+            if command.find(name) >= 0:
+                op = OPERATORS[name]
+                lhs_s, rhs_s = command.split(f" {name} ")
+                break
+
+        lhs_s, lhs_fn = value_of(lhs_s)
+        rhs_s, rhs_fn = value_of(rhs_s)
+
+        signals[signal] = ((lhs_s, rhs_s), (lhs_fn, rhs_fn), op)
+
+
+def process(
+    signals: Signals,
+    values: dict[str, int],
+) -> dict[str, int]:
+    while signals:
+        signal = next(s for s in signals if all(p in values for p in signals[s][0]))
+        _, deps, command = signals[signal]
+        values[signal] = command(deps[0](values), deps[1](values)) % 65536
+        del signals[signal]
+
+    return values
+
+
+values_1 = process(signals.copy(), values.copy())
+logging.info("\n" + "\n".join(f"{k}: {values_1[k]}" for k in sorted(values_1)))
+answer_1 = values_1["a"]
+print(f"answer 1 is {answer_1}")
+
+values_2 = process(signals.copy(), values | {"b": values_1["a"]})
+answer_2 = values_2["a"]
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day8.py

@@ -0,0 +1,35 @@
+import logging
+import os
+import sys
+
+VERBOSE = os.getenv("AOC_VERBOSE") == "True"
+logging.basicConfig(level=logging.INFO if VERBOSE else logging.WARNING)
+
+
+lines = sys.stdin.read().splitlines()
+
+answer_1 = sum(
+    # left and right quotes (not in memory)
+    2
+    # each \\ adds one character in the literals (compared to memory)
+    + line.count(R"\\")
+    # each \" adds one character in the literals (compared to memory)
+    + line[1:-1].count(R"\"")
+    # each \xFF adds 3 characters in the literals (compared to memory), but we must not
+    # count A\\x (A != \), but we must count A\\\x (A != \) - in practice we should also
+    # avoid \\\\x, etc., but this does not occur in the examples and the actual input
+    + 3 * (line.count(R"\x") - line.count(R"\\x") + line.count(R"\\\x"))
+    for line in lines
+)
+print(f"answer 1 is {answer_1}")
+
+answer_2 = sum(
+    # needs to wrap in quotes (2 characters)
+    2
+    # needs to escape every \ with an extra \
+    + line.count("\\")
+    # needs to escape every " with an extra \ (including the first and last ones)
+    + line.count('"')
+    for line in lines
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2015/day9.py

@@ -0,0 +1,26 @@
+import itertools
+import sys
+from collections import defaultdict
+from typing import cast
+
+import parse  # type: ignore
+
+lines = sys.stdin.read().splitlines()
+
+distances: dict[str, dict[str, int]] = defaultdict(dict)
+for line in lines:
+    origin, destination, length = cast(
+        tuple[str, str, int], parse.parse("{} to {} = {:d}", line)  # type: ignore
+    )
+    distances[origin][destination] = distances[destination][origin] = length
+
+distance_of_routes = {
+    route: sum(distances[o][d] for o, d in zip(route[:-1], route[1:]))
+    for route in map(tuple, itertools.permutations(distances))
+}
+
+answer_1 = min(distance_of_routes.values())
+print(f"answer 1 is {answer_1}")
+
+answer_2 = max(distance_of_routes.values())
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2021/day9.py

@@ -0,0 +1,44 @@
+import sys
+from math import prod
+
+values = [[int(c) for c in row] for row in sys.stdin.read().splitlines()]
+n_rows, n_cols = len(values), len(values[0])
+
+
+def neighbors(point: tuple[int, int]):
+    i, j = point
+    for di, dj in ((-1, 0), (+1, 0), (0, -1), (0, +1)):
+        if 0 <= i + di < n_rows and 0 <= j + dj < n_cols:
+            yield (i + di, j + dj)
+
+
+def basin(start: tuple[int, int]) -> set[tuple[int, int]]:
+    visited: set[tuple[int, int]] = set()
+    queue = [start]
+
+    while queue:
+        i, j = queue.pop()
+
+        if (i, j) in visited or values[i][j] == 9:
+            continue
+
+        visited.add((i, j))
+        queue.extend(neighbors((i, j)))
+
+    return visited
+
+
+low_points = [
+    (i, j)
+    for i in range(n_rows)
+    for j in range(n_cols)
+    if all(values[ti][tj] > values[i][j] for ti, tj in neighbors((i, j)))
+]
+
+# part 1
+answer_1 = sum(values[i][j] + 1 for i, j in low_points)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = prod(sorted(len(basin(point)) for point in low_points)[-3:])
+print(f"answer 2 is {answer_2}")