aoc2023/d03/part2.py

import sys
from collections import defaultdict as dd

G = [ list(l[:-1])  for l in sys.stdin.readlines()]

W = len(G[0])
H = len(G)

def get_G(x,y):
    return '.' if x<0 or y<0 or x>W-1 or y>H-1 else G[y][x]

c = 0  # current star
valid = None
Rs = dd(list)
for y in range(H):
    for x in range(W):
        i = get_G(x,y)
        if not i.isdigit():
            # appent current if valid and reset
            if valid:
                Rs[valid].append(c)
            valid = None
            c = 0
        else:
            c = c*10+int(i)
            for dx in [-1,0,1]:
                for dy in [-1,0,1]:
                    if '*' == get_G(x+dx,y+dy):
                        valid = (x+dx,y+dy)

print(
    sum( v[0] * v[1] for _,v in Rs.items() if len(v)==2)
)