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#advent of code 2025
#day 04
part1=0;
part2=0;
wall=set();
PuzzleInput=open("04.in","r");
adjacent=[(-1,-1),(0,-1),(1,-1),(-1,0),(1,0),(-1,1),(0,1),(1,1)];
def IsAccessible(grid,p):
neighbors=0;
px,py=p;
for dx,dy in adjacent:
neighbors+=(px+dx,py+dy) in grid;
return neighbors<4;
#parsing
for y,line in enumerate(PuzzleInput):
for x,c in enumerate(line[:-1]):
if c=="@": wall.add((x,y));
PuzzleInput.close();
#solution
while True:
removed=set();
for pos in wall:
if IsAccessible(wall,pos):
removed.add(pos);
if len(removed)==0: break;
wall.difference_update(removed);
if part1==0: part1+=len(removed);
part2+=len(removed);
#answers
print("part 1",part1);
print("part 2",part2);
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