25 files changed, 592 insertions, 0 deletions
diff --git a/2025/01/puzzle-1.awk b/2025/01/puzzle-1.awk
new file mode 100755
index 0000000..4ed1d7f
--- /dev/null
+++ b/2025/01/puzzle-1.awk
@@ -0,0 +1,19 @@
+#!/usr/bin/awk -f
+
+function mod(n, m)
+{
+	return ((n % m) + m) % m
+}
+
+BEGIN { dial = 50 }
+
+/^L/ { sign = -1 }
+/^R/ { sign = +1 }
+
+{
+	n = substr($0, 2)
+	if ((dial = mod(dial + n*sign, 100)) == 0)
+		acc++
+}
+
+END { print acc }
diff --git a/2025/01/puzzle-2.awk b/2025/01/puzzle-2.awk
new file mode 100755
index 0000000..b0516bf
--- /dev/null
+++ b/2025/01/puzzle-2.awk
@@ -0,0 +1,23 @@
+#!/usr/bin/awk -f
+
+function mod(n, m)
+{
+	return ((n % m) + m) % m
+}
+
+BEGIN { dial = 50 }
+
+{ n = substr($0, 2) }
+
+/^L/ {
+	sign = -1
+	acc += int(n / 100) + (n%100 >= dial && dial != 0)
+}
+/^R/ {
+	sign = +1
+	acc += int((dial + n) / 100)
+}
+
+{ dial = mod(dial + n*sign, 100) }
+
+END { print acc }
diff --git a/2025/02/.gitignore b/2025/02/.gitignore
new file mode 100644
index 0000000..62d9f48
--- /dev/null
+++ b/2025/02/.gitignore
@@ -0,0 +1 @@
+puzzle-[12].sh
diff --git a/2025/02/Makefile b/2025/02/Makefile
new file mode 100644
index 0000000..c1620aa
--- /dev/null
+++ b/2025/02/Makefile
@@ -0,0 +1 @@
+include ../../Makefiles/sh.mk
diff --git a/2025/02/puzzles.sh b/2025/02/puzzles.sh
new file mode 100644
index 0000000..0ad12cc
--- /dev/null
+++ b/2025/02/puzzles.sh
@@ -0,0 +1,12 @@
+#!/bin/sh
+
+# START PART 1
+readonly REGEXP='^([0-9]+)\1$'
+# END PART 1 START PART 2
+readonly REGEXP='^([0-9]+)\1+$'
+# END PART 2
+
+tr ',' '\n' <input | while IFS=- read -r x y
+do
+	seq -f %1.0f $x $y
+done | grep -E "$REGEXP" | awk '{ n += $1 } END { print n }'
diff --git a/2025/03/.gitignore b/2025/03/.gitignore
new file mode 100644
index 0000000..60d075d
--- /dev/null
+++ b/2025/03/.gitignore
@@ -0,0 +1 @@
+puzzle-[12]
diff --git a/2025/03/Makefile b/2025/03/Makefile
new file mode 100644
index 0000000..de3f940
--- /dev/null
+++ b/2025/03/Makefile
@@ -0,0 +1 @@
+include ../../Makefiles/c.mk
diff --git a/2025/03/puzzles.c b/2025/03/puzzles.c
new file mode 100644
index 0000000..9bd68ee
--- /dev/null
+++ b/2025/03/puzzles.c
@@ -0,0 +1,48 @@
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef PART1
+	#define DIGITS ((size_t)(2))
+#else
+	#define DIGITS ((size_t)(12))
+#endif
+
+int
+main(void)
+{
+	FILE *fp = fopen("input", "r");
+	if (fp == nullptr)
+		err(EXIT_FAILURE, "failed to open input");
+
+	char *buf = nullptr;
+	size_t acc, bufsz;
+	ssize_t n;
+
+	acc = bufsz = 0;
+
+	while ((n = getline(&buf, &bufsz, fp)) != -1) {
+		if (buf[n - 1] == '\n')
+			buf[--n] = 0;
+
+		char digits[DIGITS + 1];
+		memcpy(digits, buf, DIGITS);
+		digits[DIGITS] = 0;
+
+		for (size_t i = 1; i < n - DIGITS + 1; i++) {
+			for (size_t j = 0; j < DIGITS; j++) {
+				if (buf[i + j] > digits[j])
+					memcpy(digits + j, buf + i + j, DIGITS - j);
+			}
+		}
+
+		acc += (size_t)strtol(digits, nullptr, 10);
+	}
+	if (ferror(fp))
+		err(EXIT_FAILURE, "failed to read record");
+
+	fclose(fp);
+	printf("%zu\n", acc);
+	return EXIT_SUCCESS;
+}
diff --git a/2025/04/.gitignore b/2025/04/.gitignore
new file mode 100644
index 0000000..ffc46fe
--- /dev/null
+++ b/2025/04/.gitignore
@@ -0,0 +1 @@
+puzzle-[12].py
diff --git a/2025/04/Makefile b/2025/04/Makefile
new file mode 100644
index 0000000..0a4e980
--- /dev/null
+++ b/2025/04/Makefile
@@ -0,0 +1 @@
+include ../../Makefiles/py.mk
diff --git a/2025/04/puzzles.py b/2025/04/puzzles.py
new file mode 100644
index 0000000..3558269
--- /dev/null
+++ b/2025/04/puzzles.py
@@ -0,0 +1,95 @@
+#!/usr/bin/python3
+
+import itertools
+from typing import Generator, Iterator, Self, TextIO
+
+
+class Grid:
+	@classmethod
+	def from_file(cls, f: TextIO) -> Self:
+		g = Grid()
+		g._grid = mkmap(
+			[[c for c in l if c != '\n'] for l in f.readlines()])
+		return g
+
+	def in_bounds_p(self, z: complex) -> bool:
+		return (
+			0 <= z.real < len(self._grid[0])
+			and 0 <= z.imag < len(self._grid)
+		)
+
+	def accessablep(self, z: complex) -> bool:
+		return self[z] is not None and self[z] < 4
+
+	def indicies(self) -> Iterator[complex]:
+		return itertools.starmap(complex, itertools.product(
+			range(len(self._grid[0])),
+			range(len(self._grid)),
+		))
+
+	def neighbors(self, z: complex) -> Generator[complex, None, None]:
+		for Δ in (
+			-1-1j, -1, -1+1j,
+			 0-1j,      0+1j,
+			+1-1j, +1, +1+1j,
+		):
+			if self.in_bounds_p(z + Δ):
+				yield z + Δ
+
+	def __getitem__(self, z: complex) -> int | None:
+		return self._grid[int(z.real)][int(z.imag)]
+
+	def __setitem__(self, z: complex, n: int | None) -> None:
+		self._grid[int(z.real)][int(z.imag)] = n
+
+
+def mkmap(xs: list[list[str]]) -> list[list[int]]:
+	def get(pos: complex) -> str:
+		r, i = map(int, (pos.real, pos.imag))
+		if 0 <= r < len(xs[0]) and 0 <= i < len(xs):
+			return xs[r][i]
+		return '.'
+
+	return [
+		[
+			sum(get(complex(i, j) + Δ) == '@' for Δ in [
+				-1-1j, -1, -1+1j,
+				 0-1j,      0+1j,
+				+1-1j, +1, +1+1j,
+			])
+			if get(complex(i, j)) == '@'
+			else None
+			for j in range(len(xs[i]))
+		]
+		for i in range(len(xs))
+	]
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		grid = Grid.from_file(f)
+
+	if PUZZLE_PART == 1:
+		acc = sum(grid.accessablep(z) for z in grid.indicies())
+	else:
+		acc = 0
+		while True:
+			breakp = True
+			for z in grid.indicies():
+				if not grid.accessablep(z):
+					continue
+				breakp = False
+				acc += 1
+				grid[z] = None
+				for p in grid.neighbors(z):
+					if grid[p] is not None:
+						grid[p] -= 1
+
+			if breakp:
+				break
+
+	print(acc)
+
+
+if __name__ == '__main__':
+	main()
diff --git a/2025/05/puzzle-1.awk b/2025/05/puzzle-1.awk
new file mode 100755
index 0000000..acfe21b
--- /dev/null
+++ b/2025/05/puzzle-1.awk
@@ -0,0 +1,19 @@
+#!/usr/bin/awk -f
+
+BEGIN { FS = "-" }
+
+NF == 2 {
+	xs[NR, 1] = $1
+	xs[NR, 2] = $2
+}
+
+NF == 1 {
+	for (i = 1; i <= length(xs) / 2; i++) {
+		if ($1 >= xs[i, 1] && $1 <= xs[i, 2]) {
+			cnt++
+			break
+		}
+	}
+}
+
+END { print cnt }
diff --git a/2025/05/puzzle-2.awk b/2025/05/puzzle-2.awk
new file mode 100755
index 0000000..3dfc661
--- /dev/null
+++ b/2025/05/puzzle-2.awk
@@ -0,0 +1,31 @@
+#!/usr/bin/gawk -f
+
+function rangecmp(i1, v1, i2, v2)
+{
+	return v1[1] - v2[1]
+}
+
+function max(x, y)
+{
+	return x > y ? x : y
+}
+
+BEGIN { FS = "-" }
+
+NF == 2 {
+	xs[NR][1] = $1
+	xs[NR][2] = $2
+}
+
+END {
+	asort(xs, xs, "rangecmp")
+	for (i in xs) {
+		if (xs[i][2] <= m)
+			continue
+		cnt += xs[i][2] - max(xs[i][1], m)
+		if (xs[i][1] > m)
+			cnt++
+		m = xs[i][2]
+	}
+	print cnt
+}
diff --git a/2025/06/puzzle-1.awk b/2025/06/puzzle-1.awk
new file mode 100755
index 0000000..4bb4338
--- /dev/null
+++ b/2025/06/puzzle-1.awk
@@ -0,0 +1,20 @@
+#!/usr/bin/awk -f
+
+NR == 1 {
+	for (i = 1; i <= NF; i++)
+		xs[i, 2] = 1
+}
+
+!/[+*]/ {
+	for (i = 1; i <= NF; i++) {
+		xs[i, 1] += $i
+		xs[i, 2] *= $i
+	}
+}
+
+/[+*]/ {
+	for (i = 1; i <= NF; i++)
+		total += xs[i, $i == "+" ? 1 : 2]
+}
+
+END { print total }
diff --git a/2025/06/puzzle-2.sh b/2025/06/puzzle-2.sh
new file mode 100755
index 0000000..cba270f
--- /dev/null
+++ b/2025/06/puzzle-2.sh
@@ -0,0 +1,27 @@
+#!/bin/sh
+
+{
+	printf '('
+	for i in $(seq "$(head -n1 input | wc -c)")
+	do
+		num="$(cut -c $i input | paste -sd '')"
+		num="${num%${num##*[![:space:]]}}"
+
+		case "$num" in
+		*[+*])
+			test -n "$op" && printf ') + ('
+			op="${num#${num%?}}"
+			num="${num%?}"
+			printf '%d %s ' $num "$op"
+			;;
+		'')
+			test "$op" = +
+			printf '%d' $?
+			;;
+		*)
+			printf '%d %s ' $num "$op"
+			;;
+		esac
+	done
+	printf ')\n'
+} | bc
diff --git a/2025/07/puzzle-1.py b/2025/07/puzzle-1.py
new file mode 100755
index 0000000..0c30dfa
--- /dev/null
+++ b/2025/07/puzzle-1.py
@@ -0,0 +1,23 @@
+#!/usr/bin/python3
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		grid = tuple(tuple(x.strip()) for x in f.readlines())
+
+	xs = set()
+	xs.add(grid[0].index('S'))
+	cnt = 0
+
+	for row in grid[1:]:
+		for i, ch in enumerate(row):
+			if ch == '^' and i in xs:
+				cnt += 1
+				xs.remove(i)
+				xs.add(i - 1)
+				xs.add(i + 1)
+
+	print(cnt)
+
+if __name__ == '__main__':
+	main()
diff --git a/2025/07/puzzle-2.py b/2025/07/puzzle-2.py
new file mode 100755
index 0000000..3695889
--- /dev/null
+++ b/2025/07/puzzle-2.py
@@ -0,0 +1,31 @@
+#!/usr/bin/python3
+
+import collections
+import functools
+
+
+Pos = collections.namedtuple('Pos', ['x', 'y'])
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		grid = tuple(tuple(x.strip()) for x in f.readlines())
+
+	pos = Pos(grid[0].index('S'), 0)
+	print(npaths(grid, pos))
+
+
+@functools.cache
+def npaths(grid: list[list[str]], pos: Pos) -> int:
+	if pos.y == len(grid):
+		return 1
+	if grid[pos.y][pos.x] == '^':
+		return (
+			  npaths(grid, Pos(pos.x - 1, pos.y))
+			+ npaths(grid, Pos(pos.x + 1, pos.y))
+		)
+	return npaths(grid, Pos(pos.x, pos.y + 1))
+
+
+if __name__ == '__main__':
+	main()
diff --git a/2025/08/.gitignore b/2025/08/.gitignore
new file mode 100644
index 0000000..ffc46fe
--- /dev/null
+++ b/2025/08/.gitignore
@@ -0,0 +1 @@
+puzzle-[12].py
diff --git a/2025/08/Makefile b/2025/08/Makefile
new file mode 100644
index 0000000..0a4e980
--- /dev/null
+++ b/2025/08/Makefile
@@ -0,0 +1 @@
+include ../../Makefiles/py.mk
diff --git a/2025/08/puzzles.py b/2025/08/puzzles.py
new file mode 100644
index 0000000..086baca
--- /dev/null
+++ b/2025/08/puzzles.py
@@ -0,0 +1,53 @@
+#!/usr/bin/python3
+
+import functools
+import heapq
+import itertools
+import math
+import operator
+
+
+type Point = tuple[int, int, int]
+type Circuit = set[Point]
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		boxes = [tuple(map(int, l.split(','))) for l in f.readlines()]
+
+	circuits: list[Circuit] = []
+	pairs = itertools.combinations(boxes, 2)
+	pairs = iter(sorted(pairs, key=lambda p: math.dist(*p)))
+
+# START PART 1
+	for p, q in itertools.islice(pairs, 1000):
+		connect(circuits, p, q)
+
+	lens = heapq.nlargest(3, map(len, circuits))
+	print(functools.reduce(operator.mul, lens))
+# END PART 1 START PART 2
+	while len(circuits) != 1 or len(circuits[0]) != len(boxes):
+		p, q = next(pairs)
+		connect(circuits, p, q)
+	print(p[0] * q[0])
+# END PART 2
+
+
+def connect(circuits: list[Circuit], p: Point, q: Point) -> None:
+	pc = next((c for c in circuits if p in c), None)
+	qc = next((c for c in circuits if q in c), None)
+
+	match (pc, qc):
+		case (None, None):
+			circuits.append({p, q})
+		case (x, None):
+			pc.add(q)
+		case (None, y):
+			qc.add(p)
+		case (x, y) if x is not y:
+			circuits.remove(qc)
+			pc |= qc
+
+
+if __name__ == '__main__':
+	main()
diff --git a/2025/09/puzzle-1.py b/2025/09/puzzle-1.py
new file mode 100755
index 0000000..6d42141
--- /dev/null
+++ b/2025/09/puzzle-1.py
@@ -0,0 +1,29 @@
+#!/usr/bin/python3
+
+import itertools
+
+
+type Point = tuple[int, int]
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		xs = [tuple(map(int, l.split(','))) for l in f.readlines()]
+
+	it = itertools.combinations(xs, 2)
+	it = itertools.starmap(area, it)
+	print(max(it))
+
+
+def area(p: Point, q: Point) -> int:
+	a, b = minmax(p[0], q[0])
+	c, d = minmax(p[1], q[1])
+	return (b - a + 1) * (d - c + 1)
+
+
+def minmax(x: int, y: int) -> tuple[int, int]:
+	return (x, y) if x < y else (y, x)
+
+
+if __name__ == '__main__':
+	main()
diff --git a/2025/09/puzzle-2.py b/2025/09/puzzle-2.py
new file mode 100755
index 0000000..f77c4c1
--- /dev/null
+++ b/2025/09/puzzle-2.py
@@ -0,0 +1,49 @@
+#!/usr/bin/python3
+
+import itertools
+
+
+type Point = tuple[int, int]
+type Box = tuple[int, int, int, int]
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		xs = [tuple(map(int, l.split(','))) for l in f.readlines()]
+
+	it = itertools.pairwise(xs)
+	it = itertools.starmap(tobox, it)
+	ys = list(it)
+
+	n = 0
+	it = itertools.combinations(xs, 2)
+	it = itertools.starmap(tobox, it)
+	for x in it:
+		if (_area := area(x)) <= n:
+			continue
+		a, b, c, d = x
+		for p, q, r, s in ys:
+			if a < r and b < s and c > p and d > q:
+				break
+		else:
+			n = _area
+
+	print(n)
+
+
+def tobox(p: Point, q: Point) -> Box:
+	a, b = minmax(p[0], q[0])
+	c, d = minmax(p[1], q[1])
+	return a, c, b, d
+
+
+def area(b: Box) -> int:
+	return (b[2] - b[0] + 1) * (b[3] - b[1] + 1)
+
+
+def minmax(x: int, y: int) -> tuple[int, int]:
+	return (x, y) if x < y else (y, x)
+
+
+if __name__ == '__main__':
+	main()
diff --git a/2025/10/puzzle-1.py b/2025/10/puzzle-1.py
new file mode 100755
index 0000000..e3bd232
--- /dev/null
+++ b/2025/10/puzzle-1.py
@@ -0,0 +1,49 @@
+#!/usr/bin/python3
+
+import dataclasses
+import functools
+import itertools
+import operator
+from typing import Self
+
+
+@dataclasses.dataclass
+class Machine:
+	target: int
+	buttons: list[int]
+
+	@classmethod
+	def from_record(cls, s: str) -> Self:
+		buttons: list[int] = []
+		for token in s.split(' '):
+			match token[0]:
+				case '[':
+					token = token.translate({
+						ord('.'): '0',
+						ord('#'): '1',
+					})
+					target = int(token[len(token) - 2:0:-1], base=2)
+				case '(':
+					n = 0
+					for x in map(int, token[1:-1].split(',')):
+						n |= 1 << x
+					buttons.append(n)
+		return cls(target, buttons)
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		xs = [Machine.from_record(x) for x in f.readlines()]
+	print(sum(map(fewest_clicks, xs)))
+
+
+def fewest_clicks(mach: Machine) -> int:
+	for i in itertools.count(start=1):
+		for comb in itertools.combinations(mach.buttons, i):
+			if functools.reduce(operator.xor, comb) == mach.target:
+				return i
+	# NOTREACHED
+
+
+if __name__ == '__main__':
+	main()
diff --git a/2025/11/puzzle-1.awk b/2025/11/puzzle-1.awk
new file mode 100755
index 0000000..aa752e1
--- /dev/null
+++ b/2025/11/puzzle-1.awk
@@ -0,0 +1,19 @@
+#!/usr/bin/gawk -f
+
+function npaths(src, dst,    n, i)
+{
+	if (src == dst)
+		return 1;
+	for (i in paths[src])
+		n += npaths(paths[src][i], dst)
+	return n
+}
+
+BEGIN { FS = ":? " }
+
+{
+	for (i = 2; i <= NF; i++)
+		paths[$1][i - 1] = $i
+}
+
+END { print npaths("you", "out") }
diff --git a/2025/11/puzzle-2.py b/2025/11/puzzle-2.py
new file mode 100755
index 0000000..629c10c
--- /dev/null
+++ b/2025/11/puzzle-2.py
@@ -0,0 +1,37 @@
+#!/usr/bin/python3
+
+import functools
+
+
+paths: dict[str, list[str]] = {}
+
+def main() -> None:
+	with open('input', 'r') as f:
+		for line in f.readlines():
+			x, *xs = line.split()
+			paths[x[:-1]] = xs
+
+	print(npaths('svr', 'out'))
+
+
+@functools.cache
+def npaths(
+	src: str,
+	dst: str,
+	dacp: bool = False,
+	fftp: bool = False,
+) -> bool | int:
+	return (
+		dacp and fftp
+		if src == dst else
+		sum(npaths(
+			nsrc,
+			dst,
+			dacp or src == 'dac',
+			fftp or src == 'fft',
+		) for nsrc in paths[src])
+	)
+
+
+if __name__ == '__main__':
+	main()