From 7f8895c2c1b638af36f05ca779c06e55f257d812 Mon Sep 17 00:00:00 2001
From: Stefan Harmuth <stefan.harmuth@docomodigital.com>
Date: Tue, 22 Dec 2020 08:38:38 +0100
Subject: [PATCH] day22

---
 day22.py       | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++
 inputs/22      | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
 inputs/22_test | 13 ++++++++++++
 3 files changed, 121 insertions(+)
 create mode 100644 day22.py
 create mode 100644 inputs/22
 create mode 100644 inputs/22_test

diff --git a/day22.py b/day22.py
new file mode 100644
index 0000000..91895e9
--- /dev/null
+++ b/day22.py
@@ -0,0 +1,55 @@
+import aoclib
+
+DAY = 22
+TEST_SOLUTION_PART1 = 306
+TEST_SOLUTION_PART2 = 291
+
+
+def play(player1_cards, player2_cards, recursive_combat=False):
+    previous_rounds = set()
+    while player1_cards and player2_cards:
+        if recursive_combat:
+            deck_tuple = (tuple(player1_cards), tuple(player2_cards))
+            if deck_tuple in previous_rounds:
+                return 1, player1_cards
+            else:
+                previous_rounds.add(deck_tuple)
+
+        card1 = player1_cards.pop(0)
+        card2 = player2_cards.pop(0)
+        if not recursive_combat:
+            if card1 > card2:
+                player1_cards.extend([card1, card2])
+            else:
+                player2_cards.extend([card2, card1])
+        else:
+            if len(player1_cards) >= card1 and len(player2_cards) >= card2:
+                winner, _ = play(player1_cards.copy()[:card1], player2_cards.copy()[:card2], True)
+            else:
+                winner = 1 if card1 > card2 else 2
+
+            if winner == 1:
+                player1_cards.extend([card1, card2])
+            else:
+                player2_cards.extend([card2, card1])
+
+    winner = (1, player1_cards) if len(player1_cards) else (2, player2_cards)
+    return winner
+
+
+def part1(test_mode=False, recursive_combat=False):
+    my_input = aoclib.getMultiLineInputAsArray(day=DAY, test=test_mode)
+
+    player1 = [int(x) for x in my_input[0][1:]]
+    player2 = [int(x) for x in my_input[1][1:]]
+
+    _, winner = play(player1, player2, recursive_combat)
+    answer = 0
+    for x, c in enumerate(winner):
+        answer += (len(winner) - x) * c
+
+    return answer
+
+
+def part2(test_mode=False):
+    return part1(test_mode, recursive_combat=True)
diff --git a/inputs/22 b/inputs/22
new file mode 100644
index 0000000..4aed5fe
--- /dev/null
+++ b/inputs/22
@@ -0,0 +1,53 @@
+Player 1:
+31
+24
+5
+33
+7
+12
+30
+22
+48
+14
+16
+26
+18
+45
+4
+42
+25
+20
+46
+21
+40
+38
+34
+17
+50
+
+Player 2:
+1
+3
+41
+8
+37
+35
+28
+39
+43
+29
+10
+27
+11
+36
+49
+32
+2
+23
+19
+9
+13
+15
+47
+6
+44
diff --git a/inputs/22_test b/inputs/22_test
new file mode 100644
index 0000000..391cd24
--- /dev/null
+++ b/inputs/22_test
@@ -0,0 +1,13 @@
+Player 1:
+9
+2
+6
+3
+1
+
+Player 2:
+5
+8
+4
+7
+10