sharparam.com
Code for the Advent of Code event
aoc
advent-of-code
1local input = io.open("input.txt", "r")
2
3local map = {}
4
5local deliveries = 1
6
7local santa_x = 0
8local santa_y = 0
9
10local robot_x = 0
11local robot_y = 0
12
13local mode = true
14
15local function init_pos(x, y)
16 if type(map[x]) ~= "table" then map[x] = {} end
17end
18
19local function get_pos()
20 if mode then return santa_x, santa_y else return robot_x, robot_y end
21end
22
23local function move(dx, dy)
24 if mode then
25 santa_x = santa_x + dx
26 santa_y = santa_y + dy
27 else
28 robot_x = robot_x + dx
29 robot_y = robot_y + dy
30 end
31
32 mode = not mode
33end
34
35local function deliver()
36 local x, y = get_pos()
37
38 init_pos(x, y)
39
40 if not map[x][y] then
41 map[x][y] = true
42 deliveries = deliveries + 1
43 end
44end
45
46map[santa_x] = {}
47map[santa_x][santa_y] = true
48
49local char
50
51repeat
52 char = input:read(1)
53
54 if char == "^" then
55 move(0, 1)
56 elseif char == "v" then
57 move(0, -1)
58 elseif char == "<" then
59 move(-1, 0)
60 elseif char == ">" then
61 move(1, 0)
62 end
63
64 deliver()
65until not char
66
67print("Delivered at least once to " .. deliveries .. " houses")
68
69input:close()