Initial commit with days 1 to 4.

day3/solver.py

@@ -0,0 +1,67 @@
+from typing import Iterator
+import sys
+import re
+
+mul_re = re.compile(
+    r"mul\((?P<n1>\d+),(?P<n2>\d+)\)"
+)
+
+mul_re_cond = re.compile(
+    r"mul\((?P<n1>\d+),(?P<n2>\d+)\)|(?P<do>do\(\))|(?P<dont>don't\(\))"
+)
+
+def process_basic(data) -> int:
+    total = 0
+    for match in re.finditer(mul_re, data):
+        n1 = int(match.group('n1'))
+        n2 = int(match.group('n2'))
+        total += n1 * n2
+    return total
+
+def process_cond(data):
+    # Could also split into segments between do and the next don't
+    # And process each block between them
+    # But this is simpler
+    total = 0
+    enabled = True
+    for match in re.finditer(mul_re_cond, data):
+        if match.group('do'):
+            enabled = True
+        elif match.group('dont'):
+            enabled = False
+        elif enabled:
+            n1 = int(match.group('n1'))
+            n2 = int(match.group('n2'))
+            total += n1 * n2
+    return total
+
+
+def load_data(filename) -> str:
+    with open(filename) as f:
+        return f.read()
+
+def test():
+    print("Beginning Test 1")
+    data = r"xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))"
+    assert process_basic(data) == 161
+    print("Test 1 passed")
+
+    print("Beginning Test 2")
+    data = r"xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))"
+    assert process_cond(data) == 48
+    print("Test 2 passed")
+
+def main():
+    test()
+    data = load_data(sys.argv[1])
+    total = process_basic(data)
+    print(f"Total from data without conditionals: {total}")
+    total = process_cond(data)
+    print(f"Total from data with conditionals: {total}")
+
+
+
+
+
+if __name__ == '__main__':
+    main()