Add advent code for 2020 days 1-4

day_1/info.md

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+https://adventofcode.com/2020/day/1

day_1/part_1.py

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+filename = input("Filename: ")
+
+with open(filename) as file:
+	data = file.read().split("\n")
+
+for number_1 in data:
+	n1 = int(number_1)
+	for number_2 in data:
+		n2 = int(number_2)
+		if number_1 != number_2:
+			if n1 + n2 == 2020:
+				print(f"{n1} * {n2} = {n1 * n2}")

day_1/part_2.py

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+filename = input("Filename: ")
+
+with open(filename) as file:
+	data = file.read().split("\n")
+
+for number_1 in data:
+	n1 = int(number_1)
+	for number_2 in data:
+		n2 = int(number_2)
+		for number_3 in data:
+			n3 = int(number_3)
+			if number_1 != number_2 and number_2 != number_3:
+				if n1 + n2 + n3 == 2020:
+					print(f"{n1} * {n2} * {n3} = {n1 * n2 * n3}")

day_2/info.md

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+https://adventofcode.com/2020/day/2

day_2/part_1.py

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+with open("input") as file:
+	data = file.read().split("\n")
+
+import re
+
+valid_passwords = 0
+
+
+for password_data in data:
+
+	rule, password = password_data.split(": ")
+	rules = rule.split(" ")
+	min_len, max_len = rules[0].split("-")
+
+	if int(min_len) <= len(re.findall(rules[1], password)) <= int(max_len):
+		valid_passwords += 1
+
+print(valid_passwords)

day_2/part_2.py

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+with open("input") as file:
+	data = file.read().split("\n")
+
+import re
+
+valid_passwords = 0
+
+
+for password_data in data:
+
+	rule, password = password_data.split(": ")
+	rules = rule.split(" ")
+	char = rules[1]
+	pos1, pos2 = rules[0].split("-")
+
+	if password[int(pos1)-1] == char and not password[int(pos2)-1] == char:
+		valid_passwords += 1
+	if not password[int(pos1)-1] == char and password[int(pos2)-1] == char:
+		valid_passwords += 1
+
+print(valid_passwords)

day_3/info.md

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+https://adventofcode.com/2020/day/3

day_3/part_1.py

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+with open("input") as f:
+	hill = f.read().split("\n")
+
+# Index deltas
+slope = [
+	1, # the change in vertical height of the toboggan
+	3  # the change in horizontal distance of the toboggan
+]
+
+# The starting position of the toboggan
+position = [0, 0]
+
+tree_count = 0
+
+
+while position[0] < len(hill):
+
+	# Wrap the pattern as needed
+	if position[1] >= len(hill[position[0]]):
+		position[1] -= len(hill[position[0]])
+
+	# Check for trees
+	if hill[position[0]][position[1]] == "#":
+		tree_count += 1
+
+
+	position[0] += slope[0]
+	position[1] += slope[1]
+
+print(f"Trees Hit: {tree_count}")

day_3/part_2.py

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+with open("input") as f:
+	hill = f.read().split("\n")
+
+# Index deltas
+slopes = [
+	[1, 1], # right 1, down 1
+	[1, 3], # right 3, down 1
+	[1, 5], # right 5, down 1
+	[1, 7], # right 7, down 1
+	[2, 1]  # right 1, down 2
+]
+
+# The starting position of the toboggan
+
+tree_counts = []
+
+for slope in slopes:
+
+	position = [0, 0]
+	tree_count = 0
+
+	while position[0] < len(hill):
+
+		# Wrap the pattern as needed
+		if position[1] >= len(hill[position[0]]):
+			position[1] -= len(hill[position[0]])
+
+		# Check for trees
+		if hill[position[0]][position[1]] == "#":
+			tree_count += 1
+
+
+		position[0] += slope[0]
+		position[1] += slope[1]
+
+	tree_counts.append(tree_count)
+
+total = 1
+for x in tree_counts:
+	total *= x
+print(tree_counts, total)

day_4/info.md

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+https://adventofcode.com/2020/day/4
+
+
+Part 1 Wrong Answers:
+ - `260` (too low)
+
+Part 2 Wrong Answers:
+ - `225` (too high)

day_4/part_1.py

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+with open("input") as f:
+	data = [x.replace("\n", " ") for x in f.read().split("\n\n")]
+
+# The fields that passports have, if True, it's required, if False, it's an
+# optional field
+fields = {
+	"byr": True,
+	"iyr": True,
+	"eyr": True,
+	"hgt": True,
+	"hcl": True,
+	"ecl": True,
+	"pid": True,
+	"cid": False
+}
+
+valid_passports = len(data)
+
+for passport in data:
+	for field, required in fields.items():
+		if field not in passport and required:
+			valid_passports -= 1
+			break
+
+print(f"Valid Passports: {valid_passports}")

day_4/part_2.py

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+import re
+
+with open("input") as f:
+	data = [x.replace("\n", " ") for x in f.read().split("\n\n")]
+
+# The fields that passports have
+fields = [
+	"byr",
+	"iyr",
+	"eyr",
+	"hgt",
+	"hcl",
+	"ecl",
+	"pid"
+]
+
+def year_validate(min, provided, max):
+	return int(min) <= int(provided) <= int(max)
+
+def size_validate(height):
+	if height.endswith("cm"):
+		return 150 <= int(height[:-2]) <= 193
+	elif height.endswith("in"):
+		return 59 <= int(height[:-2]) <= 76
+	return False
+
+def hair_validate(colour):
+	return re.match(r"#[\w]{6}", str(colour)) != None
+
+def eye_validate(colour):
+	return colour in ("amb", "blu", "brn", "gry", "grn", "hzl", "oth")
+
+def pid_validate(id):
+	return re.match(r"^[0-9]{9}$", str(id)) != None
+
+valid_passports = 0
+
+# Check all the passports for valid data
+for passport in data:
+	valid = True
+
+	# Check each required field
+	for field in fields:
+
+		# Ensure passport has field
+		if (i := passport.find(field)) != -1:
+			value = passport[i:].split(" ")[0].split(":")[1]
+
+			if field == "byr":
+				if not year_validate(1920, value, 2002):
+					valid = False
+					break
+			elif field == "iyr":
+				if not year_validate(2010, value, 2020):
+					valid = False
+					break
+			elif field == "eyr":
+				if not year_validate(2020, value, 2030):
+					valid = False
+					break
+			elif field == "hgt":
+				if not size_validate(value):
+					valid = False
+					break
+			elif field == "hcl":
+				if not hair_validate(value):
+					valid = False
+					break
+			elif field == "ecl":
+				if not eye_validate(value):
+					valid = False
+					break
+			elif field == "pid":
+				if not pid_validate(value):
+					valid = False
+					break
+		else:
+			valid = False
+
+	if valid:
+		valid_passports += 1
+
+
+print(f"Valid Passports: {valid_passports}")