def read_file(): with open("input.txt","r") as f: return f.read().split('\n') def find_row(rowpart): row = [*range(128)] # create a list using unpack operator for c in rowpart: if c == 'F': row = row[:len(row)//2] # lower half elif c == 'B': row = row[len(row)//2:] # upper half else: break return row[0] # extract from list def find_col(colpart): col = [*range(8)] # create a list using unpack operator for c in colpart: if c == 'L': col = col[:len(col)//2] # lower half elif c == 'R': col = col[len(col)//2:] # upper half else: break return col[0] # extract from list def id(seat): rowpart = seat[:-3] colpart = seat[7:] row = find_row(rowpart) col = find_col(colpart) return 8*row + col def part1(seats): max_id = 0 for seat in seats: if id(seat) > max_id: max_id = id(seat) return max_id def part2(seats): ids = sorted(map(id, seats)) prev_id = 0 for seat_id in ids: if seat_id - prev_id == 2: # gap detected return seat_id - 1 # so your seat is the one right before prev_id = seat_id def main(): seats = read_file() print(f'{part1(seats)=}') print(f'{part2(seats)=}') if __name__ == "__main__": main()