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authorMarcin Chrzanowski <marcin.j.chrzanowski@gmail.com>2020-12-25 15:49:44 +0100
committerMarcin Chrzanowski <marcin.j.chrzanowski@gmail.com>2020-12-25 15:49:44 +0100
commit0df6aa12fd433f7fefc5302f712c3060615cda0f (patch)
tree0d876e6a86c6c7266620064abd2232ddb036f625 /22
parent52268f4b32bb92b42d855dcc2788de45bb313a4d (diff)
Add day 22
Diffstat (limited to '22')
-rw-r--r--22/a.lua40
-rw-r--r--22/b.lua83
-rw-r--r--22/input.txt53
3 files changed, 176 insertions, 0 deletions
diff --git a/22/a.lua b/22/a.lua
new file mode 100644
index 0000000..50cd196
--- /dev/null
+++ b/22/a.lua
@@ -0,0 +1,40 @@
+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
+
+ended = false
+
+while #deck1 > 0 and #deck2 > 0 do
+ card1 = table.remove(deck1, 1)
+ card2 = table.remove(deck2, 1)
+ if card1 > card2 then
+ table.insert(deck1, card1)
+ table.insert(deck1, card2)
+ else
+ table.insert(deck2, card2)
+ table.insert(deck2, card1)
+ end
+end
+
+deck = deck1
+if #deck1 == 0 then
+ deck = deck2
+end
+
+score = 0
+for i = 1, #deck do
+ score = score + i * (deck[#deck - i + 1])
+end
+print(score)
diff --git a/22/b.lua b/22/b.lua
new file mode 100644
index 0000000..ed6e862
--- /dev/null
+++ b/22/b.lua
@@ -0,0 +1,83 @@
+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))
diff --git a/22/input.txt b/22/input.txt
new file mode 100644
index 0000000..62dc0e5
--- /dev/null
+++ b/22/input.txt
@@ -0,0 +1,53 @@
+Player 1:
+29
+21
+38
+30
+25
+7
+2
+36
+16
+44
+20
+12
+45
+4
+31
+34
+33
+42
+50
+14
+39
+37
+11
+43
+18
+
+Player 2:
+32
+24
+10
+41
+13
+3
+6
+5
+9
+8
+48
+49
+46
+17
+22
+35
+1
+19
+23
+28
+40
+26
+47
+15
+27