Add 2022/18 py

erikw · erikw · commit 2e9cd975e2b1 · 2025-09-11T15:29:08.000+02:00
diff --git a/2022/18/README.md b/2022/18/README.md
@@ -0,0 +1,12 @@
+# Advent of Code - 2022 Day 18
+Here are my solutions to this puzzle.
+
+* Problem instructions: [adventofcode.com/2022/day/18](https://adventofcode.com/2022/day/18)
+* Input: [adventofcode.com/2022/day/18/input](https://adventofcode.com/2022/day/18/input)
+
+Fetch input by exporting `$AOC_SESSION` in your shell and then:
+```bash
+curl -OJLsb session=$AOC_SESSION adventofcode.com/2022/day/18/input
+```
+
+or run `fetch_input.sh` in this directory.
diff --git a/2022/18/fetch_input.sh b/2022/18/fetch_input.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+# Make sure $AOC_SESSION is exported before running this script.
+
+curl --remote-name --remote-header-name --silent --fail -A 'https://erikw.me/contact' --cookie "session=$AOC_SESSION" "https://adventofcode.com/2022/day/18/input"
+test "$?" -eq 0 && echo "Fetched input" && exit 0 || echo "Failed to fetch input" && exit 1
diff --git a/2022/18/input1.0 b/2022/18/input1.0
@@ -0,0 +1,2 @@
+1,1,1
+2,1,1
diff --git a/2022/18/input1.1 b/2022/18/input1.1
@@ -0,0 +1,13 @@
+2,2,2
+1,2,2
+3,2,2
+2,1,2
+2,3,2
+2,2,1
+2,2,3
+2,2,4
+2,2,6
+1,2,5
+3,2,5
+2,1,5
+2,3,5
diff --git a/2022/18/instructions.url b/2022/18/instructions.url
@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL=https://adventofcode.com/2022/day/18
diff --git a/2022/18/output1.0 b/2022/18/output1.0
@@ -0,0 +1 @@
+10
diff --git a/2022/18/output1.1 b/2022/18/output1.1
@@ -0,0 +1 @@
+64
diff --git a/2022/18/output2.0 b/2022/18/output2.0
@@ -0,0 +1 @@
+10
diff --git a/2022/18/output2.1 b/2022/18/output2.1
@@ -0,0 +1 @@
+58
diff --git a/2022/18/part1.py b/2022/18/part1.py
@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+import fileinput
+
+
+def droplet_scan():
+    return [tuple(int(c) for c in line.split(",")) for line in fileinput.input()]
+
+
+DELTAS = [
+    (-1, 0, 0),
+    (1, 0, 0),
+    (0, -1, 0),
+    (0, 1, 0),
+    (0, 0, -1),
+    (0, 0, 1),
+]
+
+
+def neighbours(droplet):
+    for delta in DELTAS:
+        yield tuple(a + b for a, b in zip(droplet, delta))
+
+
+def main():
+    droplets = droplet_scan()
+    sides = sum(dn not in droplets for d in droplets for dn in neighbours(d))
+    print(sides)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/2022/18/part1_comb.py b/2022/18/part1_comb.py
@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+import fileinput
+import itertools
+
+
+def droplet_scan():
+    return [tuple(int(c) for c in line.split(",")) for line in fileinput.input()]
+
+
+def droplets_connected(d1, d2):
+    # If the cubes have 2 coordinates in common, and the other is max 1 in difference.
+    return (
+        sum([x == y for (x, y) in zip(d1, d2)]) == 2
+        and sum([abs(x - y) for x, y in zip(d1, d2)]) == 1
+    )
+
+
+def main():
+    droplets = droplet_scan()
+    sides = len(droplets) * 6
+    sides_connected = 0
+
+    for d1, d2 in itertools.combinations(droplets, 2):
+        if droplets_connected(d1, d2):
+            sides_connected += 2
+
+    area = int(sides - sides_connected)
+    print(area)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/2022/18/part2.py b/2022/18/part2.py
@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+import fileinput
+from functools import reduce
+
+DELTAS = [
+    (-1, 0, 0),
+    (1, 0, 0),
+    (0, -1, 0),
+    (0, 1, 0),
+    (0, 0, -1),
+    (0, 0, 1),
+]
+
+
+def droplet_scan():
+    return [tuple(int(c) for c in line.split(",")) for line in fileinput.input()]
+
+
+def neighbours(droplet):
+    return set([tuple(a + b for a, b in zip(droplet, delta)) for delta in DELTAS])
+
+
+def minmax(items):
+    return reduce(
+        lambda acc, x: (min(acc[0], x), max(acc[1], x)), items, (items[0], items[0])
+    )
+
+
+def main():
+    droplets = droplet_scan()
+
+    x_min, x_max = minmax([x for x, _, _ in droplets])
+    y_min, y_max = minmax([y for _, y, _ in droplets])
+    z_min, z_max = minmax([z for _, _, z in droplets])
+
+    def in_bounds(x, y, z):
+        return (
+            x_min - 1 <= x <= x_max + 1
+            and y_min - 1 <= y <= y_max + 1
+            and z_min - 1 <= z <= z_max + 1
+        )
+
+    # Starting point somewhere outside lava.
+    stack = [(x_min - 1, y_min - 1, z_min - 1)]
+    seen = set()
+
+    # DFS explore droplets outside the lava that are within bounds of the lava.
+    # h/t https://www.reddit.com/r/adventofcode/comments/zoqhvy/comment/j0oul0u/
+    while stack:
+        droplet = stack.pop()
+        seen.add(droplet)
+        for droplet_n in neighbours(droplet):
+            if (
+                in_bounds(*droplet_n)
+                and droplet_n not in droplets
+                and droplet_n not in seen
+            ):
+                assert droplet_n not in seen
+                stack.append(droplet_n)
+
+    # Count how many found the dropelts are actual neighbours of the lava.
+    sides = 0
+    for droplet in droplets:
+        for droplet_n in neighbours(droplet):
+            if droplet_n in seen:
+                sides += 1
+    print(sides)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/bin/solve_day.sh b/bin/solve_day.sh
@@ -107,7 +107,7 @@ else
 
 	test "$day" == 25 && p2="" || p2="| tabedit part2.${arg_lang}"
 	# vim alias not set to nvim, assume $EDITOR is a proper editor (=vi-like).
-	$EDITOR -c "sp input | tabedit input1.0 | sp output1.0 $p2 | mksession! | normal 2gt" part1."${arg_lang}"
+	$EDITOR -c "sp input | tabedit output1.0 | aboveleft split input1.0 $p2 | mksession! | normal 2gt" part1."${arg_lang}"
 fi
 
 

-Original file line number
+Diff line change
@@ @@ -0,0 +1,13 @@ @@
 +2,2,2
 +1,2,2
 +3,2,2
 +2,1,2
 +2,3,2
 +2,2,1
 +2,2,3
 +2,2,4
 +2,2,6
 +1,2,5
 +3,2,5
 +2,1,5
 +2,3,5
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+[InternetShortcut]`
	`2`	`+URL=https://adventofcode.com/2022/day/18`