🌋

VERSION

@@ -1 +1 @@
-🪨
+🌋

makefile

@@ -14,12 +14,6 @@ CODE := $(BASE).py
 DATA := $(BASE).dat
 TEST := $(BASE).dtt
 
-save:
-	git add .
-	test `git log -1 --format=%s` == `cat VERSION` \
-		&& git commit --amend --reuse-message=head \
-		|| git commit -m `cat VERSION`
-	git log -1
 
 main: ${TEST}
 	echo 'test':
@@ -29,6 +23,12 @@ clean: ${DATA}
 	echo 'real:'
 	cat ${DATA} | docker compose run --rm advent python -u ${CODE}
 
+save:
+	git add .
+	test `git log -1 --format=%s` == `cat VERSION` \
+		&& git commit --amend --reuse-message=head \
+		|| git commit -m `cat VERSION`
+
 ${DATA} ${TEST}:
 	# avoid spam in the lead up to the event
 	test ${DAY} -le `date +%d` || test ${YEAR} -lt `date +%Y`

y2023/p13.py

@@ -0,0 +1,15 @@
+def solve(string, count):
+    plain = [ln for ln in string.splitlines()]
+    transposed = [''.join(ln) for ln in zip(*string.splitlines())]
+    for grid, m in [(plain, 100), (transposed, 1)]:
+        for idx in range(1, len(grid)):
+            aa, bb = '\n'.join(grid[:idx][::-1]), '\n'.join(grid[idx:])
+            aa, bb = sorted([aa, bb], key=len)
+            aa, bb = set(enumerate(aa)), set(enumerate(bb))
+            if len(aa - bb) == count:
+                return idx * m
+
+
+strings = open(0).read().split('\n\n')
+print(sum(solve(string, 0) for string in strings))
+print(sum(solve(string, 1) for string in strings))

y2023/p14.py

@@ -0,0 +1,50 @@
+def parse(string):
+    return {
+        complex(x, y): val
+        for y, row in enumerate(string.splitlines())
+        for x, val in enumerate(row)
+    }
+
+
+def render(grid):
+    xmin, *_, xmax = sorted({int(p.real) for p in grid})
+    ymin, *_, ymax = sorted({int(p.imag) for p in grid})
+    for y in range(ymin, ymax + 1):
+        for x in range(xmin, xmax + 1):
+            print(grid[complex(x, y)], end='')
+        print()
+
+
+def rotate(grid, angle):
+    swaps_ongoing = 1
+    while swaps_ongoing:
+        swaps_ongoing = 0
+        for pos, val in grid.items():
+            if val == 'O':
+                while grid.get(pos + angle) == '.':
+                    pos, old = pos + angle, pos
+                    grid[pos], grid[old] = val, '.'
+                    swaps_ongoing += 1
+    return grid
+
+
+def calc_load(state):
+    return int(sum(height - p.imag + 1 for p, val in state.items() if val == 'O'))
+
+
+text = open(0).read()
+grid = parse(text)
+height = max(p.imag for p in grid)
+print(calc_load(rotate(grid, -1j)))
+
+seq = []
+while True:
+    signature = frozenset(grid.items())
+    if signature in seq:
+        break
+    seq.append(signature)
+    for angle in [-1j, -1, 1j, 1]:
+        grid = rotate(grid, angle)
+prelude = seq.index(signature)
+cycle_length = len(seq) - prelude
+print(calc_load(dict(seq[prelude + (1_000_000_000 - prelude) % cycle_length])))