day12/ship-2.py

   1 #!/usr/bin/python3
   2
   3 import sys
   4
   5 waypoint_horz=10
   6 waypoint_vert=1
   7 directions=["E", "S", "W", "N"]
   8 ship_x=0
   9 ship_y=0
  10
  11 def do_waypoint_move(direction, amount):
  12     global waypoint_horz
  13     global waypoint_vert
  14     if direction in ["E", "W"]:
  15         if direction == "W":
  16             amount=amount*-1
  17         waypoint_horz+=amount
  18     elif direction in ["N", "S"]:
  19         if direction == "S":
  20             amount=amount*-1
  21         waypoint_vert+=amount
  22
  23 def turn(amount,multiplier):
  24     global waypoint_horz,waypoint_vert
  25     steps=int(amount / 90)
  26     steps=steps * multiplier
  27
  28     print("Started at: {},{} rotating {}".format(waypoint_horz,waypoint_vert,amount*multiplier))
  29     print("Steps: {}".format(steps))
  30     # translate left in to moves right
  31     if (steps < 0):
  32         steps=4+steps
  33
  34     if steps == 4 or steps == 0:
  35         return
  36
  37     print("Steps: {}".format(steps))
  38
  39     # and now we just step round that many steps to the right
  40     # now 1,2 will go round to 2,-1, i.e. x,y -> y,-x
  41     for step in range(steps):
  42         temp=waypoint_vert
  43         waypoint_vert=(waypoint_horz*-1)
  44         waypoint_horz=temp
  45
  46     print("Ended at: {},{}".format(waypoint_horz,waypoint_vert))
  47
  48 def do_ship_move(amount):
  49     global waypoint_horz,waypoint_vert,ship_x,ship_y
  50     print("Waypoint {},{}, Ship {},{}, Amount {}".format(waypoint_horz, waypoint_vert, ship_x, ship_y, amount))
  51     ship_x+=(amount*waypoint_horz)
  52     ship_y+=(amount*waypoint_vert)
  53     print("Ship {},{}".format(ship_x, ship_y))
  54
  55 def turn_right(amount):
  56     turn(amount, 1)
  57
  58 def turn_left(amount):
  59     turn(amount, -1)
  60
  61 filename="input.txt"
  62
  63 if len(sys.argv) > 1:
  64     filename=sys.argv[1]
  65
  66 for line in open(filename, "r"):
  67     line=line.rstrip()
  68     command=line[0]
  69     amount=int(line[1:])
  70
  71     if command in [ "N", "S", "E", "W" ]:
  72         do_waypoint_move(command, amount)
  73     elif command == "R":
  74         turn_right(amount)
  75     elif command == "L":
  76         turn_left(amount)
  77     elif command == "F":
  78         do_ship_move(amount)
  79
  80 print("Moved to {}, {} - MD: {}".format(ship_x,ship_y,(abs(ship_x)+abs(ship_y))))