From 99a7d62c30069a5ffe2210a72c7cf81e76a1f241 Mon Sep 17 00:00:00 2001
From: blenovo <bk@gmail.com>
Date: Wed, 16 Jul 2025 18:55:48 +0200
Subject: summertime warmup session with 2020 event

---
 2020/aoc2020-d01-1.py |  1 -
 2020/aoc2020-d01.py   | 22 ++++++++++++
 2020/aoc2020-d02.py   | 22 ++++++++++++
 2020/aoc2020-d03.py   | 29 ++++++++++++++++
 2020/aoc2020-d04.py   | 42 +++++++++++++++++++++++
 2020/aoc2020-d05.py   | 33 ++++++++++++++++++
 2020/aoc2020-d06.py   | 22 ++++++++++++
 2020/aoc2020-d07.py   | 48 ++++++++++++++++++++++++++
 2020/aoc2020-d08.py   | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2020/aoc2020-d09.py   | 55 ++++++++++++++++++++++++++++++
 2020/aoc2020-d10.py   | 39 +++++++++++++++++++++
 11 files changed, 405 insertions(+), 1 deletion(-)
 delete mode 100644 2020/aoc2020-d01-1.py
 create mode 100644 2020/aoc2020-d01.py
 create mode 100644 2020/aoc2020-d02.py
 create mode 100644 2020/aoc2020-d03.py
 create mode 100644 2020/aoc2020-d04.py
 create mode 100644 2020/aoc2020-d05.py
 create mode 100644 2020/aoc2020-d06.py
 create mode 100644 2020/aoc2020-d07.py
 create mode 100644 2020/aoc2020-d08.py
 create mode 100644 2020/aoc2020-d09.py
 create mode 100644 2020/aoc2020-d10.py

(limited to '2020')

diff --git a/2020/aoc2020-d01-1.py b/2020/aoc2020-d01-1.py
deleted file mode 100644
index 23d2abb..0000000
--- a/2020/aoc2020-d01-1.py
+++ /dev/null
@@ -1 +0,0 @@
-print("hello");
diff --git a/2020/aoc2020-d01.py b/2020/aoc2020-d01.py
new file mode 100644
index 0000000..84cca45
--- /dev/null
+++ b/2020/aoc2020-d01.py
@@ -0,0 +1,22 @@
+#advent of code 2020
+#day 01
+
+p1 = 0;
+p2 = 0;
+entries = [];
+PuzzleInput = open("01.in","r");
+for l in PuzzleInput: entries.append(int(l));
+PuzzleInput.close();
+for e1 in entries:
+	for e2 in entries:
+		if e1 + e2 == 2020:
+			p1 = e1*e2;
+		for e3 in entries:
+			if e1 + e2 + e3 == 2020:
+				p2 = e1*e2*e3;
+				break;
+			if p2: break;
+	if p1 and p2: break;
+
+print("part 1 =",p1);
+print("part 2 =",p2);
diff --git a/2020/aoc2020-d02.py b/2020/aoc2020-d02.py
new file mode 100644
index 0000000..9871373
--- /dev/null
+++ b/2020/aoc2020-d02.py
@@ -0,0 +1,22 @@
+#advent of code 2020
+#day 02
+
+p1 = 0;
+p2 = 0;
+PuzzleInput = open("02.in","r");
+for l in PuzzleInput:
+	rules, pwd = l.split(": ");
+	limits, letter = rules.split(" ");
+	lo, hi = limits.split("-");
+	check = pwd.count(letter);
+	if int(lo) <= check and int(hi) >= check:
+		p1 += 1;
+	v1 = pwd[int(lo)-1] == letter;
+	v2 = pwd[int(hi)-1] == letter;
+	v3 = v1 + v2;
+	v4 = v1 != v2;
+	if v3 and v4: p2 += 1;
+PuzzleInput.close();
+
+print("part 1 =",p1);
+print("part 2 =",p2);
diff --git a/2020/aoc2020-d03.py b/2020/aoc2020-d03.py
new file mode 100644
index 0000000..aa485e0
--- /dev/null
+++ b/2020/aoc2020-d03.py
@@ -0,0 +1,29 @@
+#advent of code 2020
+#day 03
+
+grid = dict();
+limY = 0;
+limX = 0;
+PuzzleInput = open("03.in","r");
+for y,line in enumerate(PuzzleInput):
+	for x, c in enumerate(line):
+		grid[(x,y)] = c;
+		limX = max(limX,x);
+	limY = max(limY,y);
+PuzzleInput.close();
+slopes = [(1,1),(3,1),(5,1),(7,1),(1,2)];
+p1 = 0;
+p2 = 1;
+for slope in slopes:
+	stepX, stepY = slope;
+	MyPosX = 0;
+	MyPosY = 0;	
+	trees = 0;
+	while MyPosY < limY :
+		MyPosX += stepX;
+		MyPosY += stepY;
+		if grid[(MyPosX%limX),MyPosY] == "#": trees +=1;
+	p2 *= trees;
+	if slope == (3,1): p1 += trees;
+print("part 1 = ",p1);
+print("part 2 = ",p2);
diff --git a/2020/aoc2020-d04.py b/2020/aoc2020-d04.py
new file mode 100644
index 0000000..22f044d
--- /dev/null
+++ b/2020/aoc2020-d04.py
@@ -0,0 +1,42 @@
+#advent of code 2020
+#day 04
+import re
+
+PuzzleInput = open("04.in","r").read()
+passports = PuzzleInput.split("\n\n");
+p1 = 0;
+p2 = 0;
+documents = dict(); 
+required = ["byr","iyr","eyr","hgt","hcl","ecl","pid"]; #puzzle description
+
+def part2(doc):
+	valid2 = True;
+	valid2 *= len(doc["byr"]) == 4 and int(doc["byr"]) >= 1920 and int(doc["byr"]) <= 2002;
+	valid2 *= len(doc["iyr"]) == 4 and int(doc["iyr"]) >= 2010 and int(doc["iyr"]) <= 2020; 
+	valid2 *= len(doc["eyr"]) == 4 and int(doc["eyr"]) >= 2020 and int(doc["eyr"]) <= 2030; 
+	valid2 *= doc["hgt"][-2:] == "cm" or doc["hgt"][-2:] == "in";
+	if doc["hgt"][-2:] == "cm": 
+		valid2 *= int(doc["hgt"][:-2]) >= 150 and int(doc["hgt"][:-2]) <= 193;
+	if doc["hgt"][-2:] == "in": 
+		valid2 *= int(doc["hgt"][:-2]) >= 59 and int(doc["hgt"][:-2]) <= 76;
+	valid2 *= doc["hcl"][0] == "#";
+	valid2 *= len(re.findall("[a-f]|[0-9]",doc["hcl"])) == 6;
+	valid2 *= doc["ecl"] in ["amb", "blu", "brn", "gry", "grn", "hzl", "oth"];
+	valid2 *= len(doc["pid"]) == 9;
+	return valid2; 
+
+for i,p in enumerate(passports):
+	p = p.replace("\n"," ")
+	documents[i] = dict();
+	for entry in p.split(" "):
+		if len(entry) == 0: continue;
+		k,v = entry.split(":");
+		documents[i][k] = v;	
+	valid = True;
+	for req in required:
+		valid *= req in documents[i];
+	p1 += 1*valid;
+	if valid: p2 += 1*part2(documents[i]);
+
+print("part 1 =",p1);
+print("part 2 =",p2);
diff --git a/2020/aoc2020-d05.py b/2020/aoc2020-d05.py
new file mode 100644
index 0000000..ffc6ffb
--- /dev/null
+++ b/2020/aoc2020-d05.py
@@ -0,0 +1,33 @@
+#advent of code 2020
+#day 05
+#examples = ["BFFFBBFRRR","FFFBBBFRRR","BBFFBBFRLL"];
+def partitioner(instr, limLow, limHigh, splitLow, splitHigh):
+	diff = limHigh - limLow + 1;
+	if instr == "":
+		return limLow;
+	elif instr[0] == splitLow:
+		return partitioner(instr[1:], limLow, limHigh-diff//2, splitLow, splitHigh);
+	elif instr[0] == splitHigh:
+		return partitioner(instr[1:], limLow+diff//2, limHigh, splitLow, splitHigh);
+
+p1 = 0;
+AllSeats = [];
+PuzzleInput = open("05.in","r");
+
+for BoardingPass in PuzzleInput:
+	BP = BoardingPass.replace("\n","");
+	row = partitioner(BP[:-3],0,127,"F","B");
+	col = partitioner(BP[-3:],0,7,"L","R");
+	seatID = row*8 + col;
+	p1 = max(p1,seatID)
+	AllSeats.append(seatID)
+PuzzleInput.close();
+
+AllSeats = sorted(AllSeats);
+for n in range(1, len(AllSeats)):
+	if AllSeats[n] - AllSeats[n-1] != 1:
+		p2 = AllSeats[n-1] + 1;
+		break;
+
+print("part 1 = ",p1);
+print("part 2 = ",p2);
diff --git a/2020/aoc2020-d06.py b/2020/aoc2020-d06.py
new file mode 100644
index 0000000..8f0df5c
--- /dev/null
+++ b/2020/aoc2020-d06.py
@@ -0,0 +1,22 @@
+#advent of code 2020
+#day 06
+PuzzleInput = open("06.in","r").read();
+groups = PuzzleInput.split("\n\n");
+p1 = 0;
+p2 = 0;
+
+for group in groups:
+	anyone = group.replace("\n","");
+	p1 += len(set(list(anyone)));
+	everyone = group.split("\n");
+	answers = [];
+	for e in everyone:
+		if len(e) == 0: continue; #some minor adjustment bc parsing
+		answers.append(set(list(e)))
+	total = answers[0]; #answers of the first guy (1st line)
+	for a in answers[1:]:
+		total = total.intersection(a); #shrink the set to duplicates only
+	p2 += len(total);
+
+print("part 1 =",p1);
+print("part 2 =",p2);
diff --git a/2020/aoc2020-d07.py b/2020/aoc2020-d07.py
new file mode 100644
index 0000000..4be155f
--- /dev/null
+++ b/2020/aoc2020-d07.py
@@ -0,0 +1,48 @@
+#advent of code 2020
+#day 07
+#cool
+PuzzleInput = open("07.in","r");
+
+rules = {};
+target = "shinygold";
+queue = [];
+options = set();
+#parse, removing filler wording and splitting bag names to dictionary
+for line in PuzzleInput:
+	line = line.replace("\n","").replace(" bags","").replace(" bag","").replace("no other","1 no other")[:-1];
+	rk, rv = line.split(" contain "); #rule key, rule value
+	rv = rv.split(", ");
+	rk = rk.replace(" ","");
+	rules[rk] = dict();
+	for rval in rv:
+		rv1,rv2,rv3 = rval.split(" ");
+		rules[rk][rv2+rv3] = int(rv1);
+	if target in rules[rk]: 
+		queue.append(rk);
+		options.add(rk);
+PuzzleInput.close();
+#part 1
+visited = [];
+while queue:
+	bag = queue.pop();
+	if bag in visited: continue;
+	visited.append(bag);
+	for rk in rules:
+		if bag in rules[rk]: 
+			queue.append(rk);
+			options.add(rk);
+
+p1 = len(options);
+#part 2
+queue = [(1,target)];
+AllBags = dict();
+while queue:
+	total, bag = queue.pop();
+	for b in rules[bag]:
+		if b == "noother": continue;
+		AllBags[b] = AllBags.get(b,0) + total*rules[bag][b];
+		queue.append((total*rules[bag][b], b));
+
+p2 = sum([AllBags[bag] for bag in AllBags]);
+print("part 1 =",p1);
+print("part 2 =",p2);
diff --git a/2020/aoc2020-d08.py b/2020/aoc2020-d08.py
new file mode 100644
index 0000000..8965514
--- /dev/null
+++ b/2020/aoc2020-d08.py
@@ -0,0 +1,93 @@
+#advent of code 2020
+#day 08
+#a little bit bruteforce-ish, 
+#for part 2 I mark instruction that are actually used by boot code
+#then I loop over the marked instructions and replace them 1 by 1 until 
+#the infinite cycle is broken
+#also the input kept getting broken and needed to change the parsing
+#which isn't a hard bug, but an annoying one
+#ALSO during rewriting I figured out that I don't need to calculate 
+#part 1 separately, it's already used during cycle detection
+#although this might just be a coincidence; honestly I'm not confident
+#in cycle detection puzzles
+
+BootCode = []
+PuzzleInput = open("08.in","r")
+for x in PuzzleInput:
+	if len(x) == 0: continue; #please ignore it, I'm bad at parsing
+	instr, val = x.split(" ");
+	BootCode.append(x.replace("\n",""));
+PuzzleInput.close();
+
+index = 0;
+accumulator = 0;
+visited = set();
+#the "Im sure it works" method for part 1
+while True:
+	instr, val = BootCode[index].split(" ");
+	#order += 1;
+	if index in visited: break;
+	visited.add(index);
+	if instr == "nop": 
+		index += 1;
+	elif instr == "acc":
+		accumulator += int(val);
+		index += 1;
+	elif instr == "jmp": 
+		index += int(val);
+
+print("part 1 =",accumulator);
+
+index = 0;
+accumulator = 0;
+accVals = dict();
+p1 = None;
+#the "it works for me but might be luck" method for part 1
+while index <= len(BootCode):
+	instr, val = BootCode[index].split(" ");
+	Current, Previous = accVals.get(index,(None,None));
+	if Previous and Current and Previous%accumulator == Previous%accumulator:
+		p1 = Current;
+		break;
+	accVals[index] = (accumulator, Current);
+	if instr == "nop": 
+		index += 1;
+	elif instr == "acc":
+		accumulator += int(val);
+		index += 1;
+	elif instr == "jmp": 
+		index += int(val);
+
+print("part 1 =",p1);
+
+p2 = None;
+for i in accVals:
+	if BootCode[i].split(" ")[0] == "acc": continue;
+	index = 0;
+	accumulator = 0;
+	accValsNested = dict();
+	NoCycle = True;
+	while index < len(BootCode):
+		instr, val = BootCode[index].split(" ");
+		Current, Previous = accValsNested.get(index,(None,None));
+		if Previous and Current and Previous%accumulator == Previous%accumulator:
+			NoCycle = False;
+			break;
+		accValsNested[index] = (accumulator, Current);
+		if index == i: #swap instructions
+			if instr == "nop": 
+				instr = "jmp";
+			elif instr == "jmp":
+				instr = "nop";
+		if instr == "nop": 
+			index += 1;
+		elif instr == "acc":
+			accumulator += int(val);
+			index += 1;
+		elif instr == "jmp": 
+			index += int(val);
+	if NoCycle:
+		p2 = accumulator;
+		break;
+
+print("part 2 =", p2);
diff --git a/2020/aoc2020-d09.py b/2020/aoc2020-d09.py
new file mode 100644
index 0000000..26c1c61
--- /dev/null
+++ b/2020/aoc2020-d09.py
@@ -0,0 +1,55 @@
+#advent of code 2020
+#day 09
+#genuinely surprised the simple solution worked
+#shamelessly googled the code for combinations, 
+#didn't feel like implementing it
+#if i reversed the "visited" list the runtime could be faster but w/e
+
+def PossibleCombs(n,k):
+	combinations = [];
+	if k==1: return n;
+	for i in range(len(n)):
+		head = n[i:i+1]
+		tail = PossibleCombs(n[i+1:],k-1);
+		for j in range(len(tail)):
+			if type(tail[j]) == int:
+				comb = head + [tail[j]]
+			else: 
+				comb = head + tail[j];
+			combinations.append(comb);
+	return combinations;
+
+p1 = None;
+limit = 25;
+numbers = [];
+PuzzleInput = open("09.in","r");
+for line in PuzzleInput: numbers.append(int(line));
+PuzzleInput.close();
+previous = numbers[:limit];
+counter = limit -1;
+
+for n in numbers[limit:]:
+	counter += 1;
+	found = False;
+	for combo in PossibleCombs(previous,2):
+		if n == sum(combo): 
+			previous = previous[1:] + [n];
+			found = True;
+			break;
+	if not found: 
+		p1 = n;
+		break;
+
+visited = numbers[:counter];
+for i,n in enumerate(visited):
+	subsum = 0 + n;
+	subcounter = 0 + i;
+	while subsum < p1:
+		subcounter += 1;
+		subsum += visited[subcounter];
+	if subsum == p1:
+		p2 = min(visited[i:subcounter]) + max(visited[i:subcounter]) ;
+		break;
+
+print("part 1 =",p1);
+print("part 2 =",p2);
diff --git a/2020/aoc2020-d10.py b/2020/aoc2020-d10.py
new file mode 100644
index 0000000..a86b976
--- /dev/null
+++ b/2020/aoc2020-d10.py
@@ -0,0 +1,39 @@
+#advent of code 2020
+#day 10
+#very similar (if not identical) to towels puzzle, 2024-d19
+#memorize previous paths and just sum up the valid paths for each adapter
+#although this one i think is easier due to no duplicates 
+#and working on numbers instead of characters
+bag = [];
+PuzzleInput = open("10.in","r");
+for num in PuzzleInput: bag.append(int(num));
+PuzzleInput.close();
+#first and last items are from puzzle description
+bag = [0] + [x for x in sorted(bag)] + [max(bag) +3]; 
+connections = dict();
+connections[1] = 0;
+connections[2] = 0;
+connections[3] = 0;
+#since there are no duplicates and all adapters must be connected
+#we can just check against the previous value for part 1;
+for index in range(1,len(bag)):
+	adapter1 = bag[index];
+	adapter2 = bag[index-1];	
+	diff = adapter1 - adapter2;
+	connections[diff] += 1;
+
+p1 = connections[1] * connections[3];
+
+p2 = 0;
+options = dict();
+options[0] = 1;
+for index in range(1,len(bag)):	
+	previous = bag[:index];
+	possible = [x for x in previous if bag[index] - x <=3];
+	options[bag[index]] = 0;
+	for poss in possible:
+		options[bag[index]] += options[poss];	
+
+p2 = options[max(bag)];
+print("part 1 =",p1);
+print("part 2 =",p2);
-- 
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