Advent of Code 2020: Python Solution Day 12

with open("day12.txt", "r") as fp: lines = [(line.rstrip()[0], int(line.rstrip()[1:])) for line in fp.readlines()] dirs = ["E", "S", "W", "N", "L", "R", "F"] curr_dir = "E" curr_state = {"E":0, "W":0, "N":0, "S":0} for line in lines: if line[0] == "F": curr_state[curr_dir] += line[1] if line[0] == "R": av = ["E", "S", "W", "N"] angle = line[1] v = int(angle/90) ndir = (av.index(curr_dir)+v) % len(av) ndir = av[ndir] curr_dir = ndir if line[0] == "L": av = ["E", "N", "W", "S"] angle = line[1] v = int(angle/90) ndir = (av.index(curr_dir)+v) % len(av) ndir = av[ndir] curr_dir = ndir if line[0] == "N": curr_state["N"] += line[1] if line[0] == "S": curr_state["S"] += line[1] if line[0] == "W": curr_state["W"] += line[1] if line[0] == "E": curr_state["E"] += line[1] d = curr_state["E"]-curr_state["W"], curr_state["S"]-curr_state["N"] print(f"Manhattan Distance of current positions from starting i.e. {curr_state} = {d[0]+d[1]}") 

# ref https://github.com/vesche/adventofcode-2020/blob/master/day12.py import math def rotate(origin, point, angle): # source: https://stackoverflow.com/a/34374437  ox, oy = origin px, py = point qx = ox + math.cos(angle) * (px - ox) - math.sin(angle) * (py - oy) qy = oy + math.sin(angle) * (px - ox) + math.cos(angle) * (py - oy) return int(round(qx)), int(round(qy)) coord = {'x': 0, 'y': 0} waypoint = {'x': 10, 'y': 1} for line in lines: instruction, n = line if instruction == 'N': waypoint['y'] += n elif instruction == 'S': waypoint['y'] -= n elif instruction == 'E': waypoint['x'] += n elif instruction == 'W': waypoint['x'] -= n elif instruction == 'F': coord['y'] += waypoint['y'] * n coord['x'] += waypoint['x'] * n elif instruction in ['L', 'R']: if instruction == 'R': n = -n waypoint['x'], waypoint['y'] = rotate( (0, 0), (waypoint['x'], waypoint['y']), math.radians(n) ) abs(coord['x']) + abs(coord['y'])