Day 2

day02.py

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+#!/usr/bin/env python
+
+import re
+from functools import reduce
+
+f = open("day02input.txt", "r")
+a = f.readline().strip().split(",")
+
+
+def get_re(pat_len: int, pat_num: int = 2) -> re.Pattern:
+  return re.compile((r"(" + r"\d" * pat_len + r")") * pat_num)
+
+def part1(data: list[str]) -> int:
+  bad_ids = 0
+  r = {}
+
+  for id_set in data:
+    _from, _to = id_set.split("-")
+    # loop over IDs in range
+    for _id in range(int(_from), int(_to) + 1):
+      id_len = len(str(_id))
+
+      # weed out IDs with odd number of digits
+      if id_len % 2 == 1:
+        continue
+
+      hl = str(id_len // 2)
+      
+      # check if compiled re is already in dict; add if not  
+      if not hl in r.keys():
+        r[hl] = get_re(int(hl))
+      
+      # match ID and check if first and second halves are equal
+      m = r[hl].match(str(_id))
+      if m.group(1) == m.group(2):
+        bad_ids += _id
+  return bad_ids
+
+def part2(data: list[str]) -> int:
+  bad_ids = set()  # collect invalid IDs in a set to avoid adding counting the same ID multiple times
+  r = {}
+
+  for id_set in data:
+    _from, _to = id_set.split("-")
+
+    # loop over IDs in range
+    for _id in range(int(_from), int(_to) + 1):
+      id_len = len(str(_id))
+
+      # loop over pattern lengths
+      for pat_len in range(1, (id_len // 2) + 1):
+        # weed out IDs where ID length is not a multiple of pattern length 
+        if id_len % pat_len != 0:
+          continue
+
+        pat_num = id_len // pat_len
+        
+        # check if compiled re is already in dict; add if not  
+        if not str(pat_len) in r.keys():
+          r[str(pat_len)] = {}
+        if not str(pat_num) in r[str(pat_len)].keys():
+          r[str(pat_len)][str(pat_num)] = get_re(pat_len, pat_num)
+          print(f"RE:\t{_id}\t\t{pat_len}\t{pat_num}\t{r[str(pat_len)][str(pat_num)]}")
+        
+        # match ID and check if all groups are equal
+        m = r[str(pat_len)][str(pat_num)].match(str(_id))
+        if len(set(m.groups())) == 1:
+          print(f"Match:\t{_id}\t\t{pat_len}\t{pat_num}\t{r[str(pat_len)][str(pat_num)]}")
+          bad_ids.add(_id)
+  return sum(bad_ids)
+
+    
+print(part1(a))
+print(part2(a))

day02input.txt

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+82853534-82916516,2551046-2603239,805115-902166,3643-7668,4444323719-4444553231,704059-804093,32055-104187,7767164-7799624,25-61,636-1297,419403897-419438690,66-143,152-241,965984-1044801,1-19,376884-573880,9440956-9477161,607805-671086,255-572,3526071225-3526194326,39361322-39455443,63281363-63350881,187662-239652,240754-342269,9371-26138,1720-2729,922545-957329,3477773-3688087,104549-119841