aoc2025-day02-part2.py

import math

l=list(map(lambda x:list(map(int,x.split("-"))), input().split(",")))

def finddup(s, e, d, l):
  if d%l!=0: return range(0,0)
  a=0
  for i in range(0, d, l):
    a+=10**i
  s=math.ceil(s/a)*a
  e=math.floor(e/a)*a
  return range(s, e+1, a)

def solve(part2):
  x=0
  for a in l:
    d1=math.ceil(math.log10(a[0]))
    d2=math.ceil(math.log10(a[1]))
    ids=set()
    for d in range(d1, d2+1):
      if part2:
        r = range(1,d)
      elif d%2==1:
        continue
      else:
        r = [int(d/2)]
      if d==d1: s=a[0]
      else:     s=10**(d-1)
      if d==d2: e=a[1]
      else:     e=10**d-1
      for i in r:
        r=finddup(s, e, d, i)
        ids.update(r)
    x+=sum(ids)
  return x

print(solve(part2=True))