Solve 02

02/solve.py

@@ -0,0 +1,62 @@
+import sys
+
+def load_words(filename):
+	words = []
+	with open(filename, "r") as f:
+		for line in f:
+			words.append(line[:-1])
+	return words
+
+# PART 1
+
+def has_n_chars(word, n):
+	count = {}
+	for char in word:
+		count[char] = count.get(char, 0) + 1
+	return n in count.values()
+
+def count_words(words):
+	twice = 0
+	thrice = 0
+	for word in words:
+		if has_n_chars(word, 2):
+			twice += 1
+		if has_n_chars(word, 3):
+			thrice += 1
+	return twice, thrice
+
+def checksum(words):
+	twice, thrice = count_words(words)
+	return twice * thrice
+
+# PART 2
+
+def differ_by(a, b):
+	count = 0
+	for x, y in zip(a, b):
+		if x != y:
+			count += 1
+	return count
+
+def find_ids(words):
+	for i, a in enumerate(words):
+		for b in words[i:]:
+			if differ_by(a, b) == 1:
+				return a, b
+
+def common_chars(a, b):
+	result = []
+	for x, y in zip(a, b):
+		if x == y:
+			result.append(x)
+	return "".join(result)
+
+def main(filename):
+	words = load_words(filename)
+	print(f"Solutions for {filename}")
+	a, b = find_ids(words)
+	print(f"Part 1: {common_chars(a, b)}")
+
+if __name__ == "__main__":
+	for filename in sys.argv[1:]:
+		main(filename)