From de308443f4ed4e12cd18578af09b93d7d01e2a84 Mon Sep 17 00:00:00 2001
From: bthink <bthink@fake.com>
Date: Fri, 12 Dec 2025 12:42:43 +0100
Subject: final week of 2025

---
 2025/aoc2025-d09.py | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 2025/aoc2025-d09.py

(limited to '2025/aoc2025-d09.py')

diff --git a/2025/aoc2025-d09.py b/2025/aoc2025-d09.py
new file mode 100644
index 0000000..df7be78
--- /dev/null
+++ b/2025/aoc2025-d09.py
@@ -0,0 +1,92 @@
+#advent of code 2025
+#day 09
+#bit slow
+#tried adding comments but will probably forget how it works anyway
+
+tiles=[];
+Ymax=0;
+Xmax=0;
+Ymin=10000000;
+Xmin=10000000;
+PuzzleInput=open("09.in","r");
+for l in PuzzleInput:
+	t=tuple([int(v) for v in l.split(",")]);
+	tiles.append(t);
+	Xmax=max(Xmax,t[0]);
+	Ymax=max(Ymax,t[1]);
+	Xmin=min(Xmin,t[0]);
+	Ymin=min(Ymin,t[1]);
+PuzzleInput.close();
+
+part1=0;
+green=set();
+for ci1,corner1 in enumerate(tiles):
+	x1,y1=corner1;
+	for ci2,corner2 in enumerate(tiles):
+		if ci1==ci2: continue;
+		x2,y2=corner2;
+		area=(abs(x1-x2)+1)*(abs(y1-y2)+1);
+		part1=max(part1,area);
+
+part2=0;
+#create the perimiter of the figure ("green" set)
+#check how big is a distance between each tile
+#tiles are ordered
+delta=[(1,0),(0,1)]
+distancedTiles=[];
+test=0;
+maxdist=0;
+for t in range(len(tiles)):
+	tile1=tiles[t];
+	tile2=tiles[(t+1)%len(tiles)];
+	for i in range(2):
+		if tile1[i]==tile2[i]: continue;
+		dx,dy=delta[i];
+		steps=tile2[i]-tile1[i];
+		dd=1*(steps>0) -1*(steps<0);
+		for step in range(abs(steps)):
+			green.add((tile1[0]+dx*dd*step,tile1[1]+dy*dd*step));
+		distancedTiles.append((abs(steps),tile1,tile2,i));
+		maxdist=max(maxdist,abs(steps));
+#sort the distances from longest to shortest
+distancedTiles=sorted(distancedTiles,key=lambda m: m[0],reverse=True);
+#check if the candidate "dt" isn't an order of 10 lower compared to biggest distance
+#the biggest area has to be along the longest edge
+candidates=[dt for dt in distancedTiles if maxdist//dt[0]<10];
+for can_i in range(len(candidates)):
+	candidate=candidates[can_i];
+	d,can1,can2,can_orient=candidate;
+	orient_1=candidates[(can_i)%len(candidates)][1][(can_orient+1)%2];
+	orient_2=candidates[(can_i+1)%len(candidates)][1][(can_orient+1)%2];
+	
+	if orient_1 > orient_2:
+		lim_1=orient_1;
+		lim_2=Ymax+1;
+	else:
+		lim_1=0;
+		lim_2=orient_1+1;
+	
+	can=sorted([can1,can2],key=lambda m:m[0])[1]
+	otherCandidates=[ocand for ocand in tiles if ocand[(can_orient+1)%2] in range(lim_1,lim_2)];
+	for ocand in otherCandidates:
+		#check if the X edge isn't in the way of perimiter (the longest edge doesn't count)
+		checkX=True;
+		for s in range(1+min(ocand[0],can[0]),max(ocand[0],can[0]) -1):
+			if can[0]==s: continue;
+			if (s,ocand[1]) in green:
+				checkX=False;
+				break;
+		if not checkX: continue;
+		#check if the Y edge isn't in the way of perimiter
+		checkY=True;
+		for s in range(1+min(ocand[1],can[1]),max(ocand[1],can[1]) -1):
+			if (can[0],s) in green:
+				checkY=False;
+				break;
+		if not checkY: continue;
+		
+		area2=(abs(can[0]-ocand[0])+1)*(abs(can[1]-ocand[1])+1);
+		part2=max(part2,area2);
+
+print("part 1 =",part1);
+print("part 2 =",part2);
-- 
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