aoc/2021/2/solution.py

#!/usr/bin/python3
import sys

class Submarine:
    def __init__(self):
        self.position = 0
        self.depth = 0
        self.direction_lookup = {
            'forward': (0, 1, 1),
            'up': (1, 0, -1),
            'down': (1, 0, 1)
        }
        print('position', self.position, self.depth)

    def encode_position(self):
        return self.position * self.depth

    def move(self, direction, units):
        try:
            vertical, horizontal, multiplier = self.direction_lookup[direction]
            self.position += horizontal * multiplier * units
            self.depth += vertical * multiplier * units
            print('new position', self.position, self.depth)
        except KeyError:
            print('invalid command')

sub = Submarine()
for line in sys.stdin:
    assert ' ' in line
    direction, units = line.rstrip('\n').split()
    print(direction, units)
    sub.move(direction, int(units))

print('distance {}'.format(sub.encode_position()))