Day 3

day03-1.py

+import logging
+import re
+
+from functools import reduce
+from itertools import pairwise
+from sys import stdout
+
+# It seems like the goal of the program is just to multiply some numbers. 
+# It does that with instructions like mul(X,Y), where X and Y are each 1-3 
+# digit numbers. For instance, mul(44,46) multiplies 44 by 46 to get a 
+# result of 2024. Similarly, mul(123,4) would multiply 123 by 4.
+
+# However, because the program's memory has been corrupted, there are also 
+# many invalid characters that should be ignored, even if they look like 
+# part of a mul instruction. Sequences like mul(4*, mul(6,9!, ?(12,34), or 
+# mul ( 2 , 4 ) do nothing.
+
+# For example, consider the following section of corrupted memory:
+
+# xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))
+
+# Adding up the result of each real instruction produces 161 
+# (2*4 + 5*5 + 11*8 + 8*5).
+
+LOG_FILENAME = "./day03-1.log"
+INPUT_FILENAME = "./input03.txt"
+
+logger = logging.Logger(__name__)
+formatter = logging.Formatter('[%(asctime)s][%(levelname)s] %(message)s')
+sh = logging.StreamHandler(stdout)
+sh.setLevel(logging.INFO)
+sh.setFormatter(formatter)
+fh = logging.FileHandler(LOG_FILENAME, mode="w", encoding="utf-8")
+fh.setLevel(logging.DEBUG)
+fh.setFormatter(formatter)
+logger.addHandler(sh)
+logger.addHandler(fh)
+
+def multiply_pair(s):
+    pair = [int(x) for x in s[4:-1].split(",")]
+    return reduce(lambda x,y: x*y, pair, 1)
+
+def main():
+    with open(INPUT_FILENAME, "r") as f:
+        line = "".join(f.readlines())
+
+    MUL_REGEX = r"mul\(\d{1,3},\d{1,3}\)"
+    matches = re.findall(MUL_REGEX, line)
+    total_sum = reduce(lambda x,y: x+y, map(multiply_pair, matches))
+    print(f"Total sum: {total_sum}")
+
+
+if __name__ == "__main__":
+    main()

day03-2.py

+import logging
+import re
+
+from functools import reduce
+from itertools import pairwise
+from sys import stdout
+
+# It seems like the goal of the program is just to multiply some numbers. 
+# It does that with instructions like mul(X,Y), where X and Y are each 1-3 
+# digit numbers. For instance, mul(44,46) multiplies 44 by 46 to get a 
+# result of 2024. Similarly, mul(123,4) would multiply 123 by 4.
+
+# However, because the program's memory has been corrupted, there are also 
+# many invalid characters that should be ignored, even if they look like 
+# part of a mul instruction. Sequences like mul(4*, mul(6,9!, ?(12,34), or 
+# mul ( 2 , 4 ) do nothing.
+
+# For example, consider the following section of corrupted memory:
+
+# xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))
+
+# Adding up the result of each real instruction produces 161 
+# (2*4 + 5*5 + 11*8 + 8*5).
+
+# There are two new instructions you'll need to handle:
+
+#     The do() instruction enables future mul instructions.
+#     The don't() instruction disables future mul instructions.
+
+# Only the most recent do() or don't() instruction applies. 
+# At the beginning of the program, mul instructions are enabled.
+
+LOG_FILENAME = "./day03-1.log"
+INPUT_FILENAME = "./input03.txt"
+
+logger = logging.Logger(__name__)
+formatter = logging.Formatter('[%(asctime)s][%(levelname)s] %(message)s')
+sh = logging.StreamHandler(stdout)
+sh.setLevel(logging.INFO)
+sh.setFormatter(formatter)
+fh = logging.FileHandler(LOG_FILENAME, mode="w", encoding="utf-8")
+fh.setLevel(logging.DEBUG)
+fh.setFormatter(formatter)
+logger.addHandler(sh)
+logger.addHandler(fh)
+
+def multiply_pair(s):
+    pair = [int(x) for x in s[4:-1].split(",")]
+    return reduce(lambda x,y: x*y, pair, 1)
+
+def main():
+    with open(INPUT_FILENAME, "r") as f:
+        line = "".join(f.readlines())
+
+    MUL_REGEX = r"((do|don't)\(\)|mul\(\d{1,3},\d{1,3}\))"
+    matches = re.findall(MUL_REGEX, line)
+    ops = [x[0] for x in matches]
+    logger.info(ops[:25])
+    good_ops = []
+    toggle = True
+    for o in ops:
+        if not toggle and o == "do()":
+            toggle = True
+            continue
+        if toggle:
+            if o == "don't()":
+                toggle = False
+                continue
+            if "mul" in o:
+                good_ops.append(o)
+
+    total_sum = reduce(lambda x,y: x+y, map(multiply_pair, good_ops))
+    logger.info(f"Total sum: {total_sum}")
+
+
+if __name__ == "__main__":
+    main()