1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
|
deck1 = {}
file = io.open('input.txt')
for line in file:lines() do
if line:find('%d+') then
table.insert(deck1, tonumber(line))
elseif line == '' then
break
end
end
deck2 = {}
for line in file:lines() do
if line:find('%d+') then
table.insert(deck2, tonumber(line))
end
end
function make_signature(deck1, deck2)
return table.concat(deck1, ',') .. '#' .. table.concat(deck2, ',')
end
function copy(deck, n)
local new_deck = {}
for i = 1, n do
table.insert(new_deck, deck[i])
end
return new_deck
end
function play_game(deck1, deck2, calculate_score)
local winner = nil
local previous_rounds = {}
while not winner do
if not previous_rounds[make_signature(deck1, deck2)] then
previous_rounds[make_signature(deck1, deck2)] = true
local card1 = table.remove(deck1, 1)
local card2 = table.remove(deck2, 1)
local one_won_round = true
if card1 <= #deck1 and card2 <= #deck2 then
one_won_round = play_game(copy(deck1, card1), copy(deck2, card2), false)
else
one_won_round = card1 > card2
end
if one_won_round then
table.insert(deck1, card1)
table.insert(deck1, card2)
else
table.insert(deck2, card2)
table.insert(deck2, card1)
end
if #deck2 == 0 then
winner = 1
elseif #deck1 == 0 then
winner = 2
end
else
winner = 1
end
end
if calculate_score then
deck = deck1
if winner == 2 then
deck = deck2
end
score = 0
for i = 1, #deck do
score = score + i * (deck[#deck - i + 1])
end
return score
end
if winner == 1 then
return true
else
return false
end
end
print(play_game(deck1, deck2, true))
|