From 661440e4cee68d130974bc9f322f15b219645680 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Anders=20Ytterstr=C3=B6m?= <yttan@fastmail.se>
Date: Sat, 4 Dec 2021 07:12:00 +0100
Subject: [PATCH] Solve 2021:4 "Giant squid"

---
 2021-python/solutions/day_04.py  | 54 +++++++++++++++++++++++++++++
 2021-python/tests/test_day_04.py | 59 ++++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)
 create mode 100644 2021-python/solutions/day_04.py
 create mode 100644 2021-python/tests/test_day_04.py

diff --git a/2021-python/solutions/day_04.py b/2021-python/solutions/day_04.py
new file mode 100644
index 0000000..9b3aa4b
--- /dev/null
+++ b/2021-python/solutions/day_04.py
@@ -0,0 +1,54 @@
+from itertools import chain
+
+from solutions import BaseSolution
+
+
+class Solution(BaseSolution):
+    input_file = "04.txt"
+
+    def __str__(self):
+        return "Day 4: Day 4: Giant Squid"
+
+    def parse_input(self, data):
+        queue, *boards = data.strip().split("\n\n")
+        queue = list(map(int, queue.split(",")))
+        boards = [[list(map(int, r.split())) for r in b.splitlines()] for b in boards]
+        return queue, boards
+
+    def solve(self, puzzle_input):
+        queue, boards = puzzle_input
+        called, winner, _i = self._play(queue, boards)
+        return self._score(called, winner)
+
+    def solve_again(self, puzzle_input):
+        queue, boards = puzzle_input
+        while (len(boards)) > 0:
+            called, winner, i = self._play(queue, boards)
+            del boards[i]
+        return self._score(called, winner)
+
+    def _score(self, called, winner):
+        return called[-1] * sum(set(chain(*winner)) - set(called))
+
+    def _play(self, queue, boards):
+        def bingo(called, numbers):
+            return numbers.issubset(called)
+
+        boards = list(
+            map(
+                lambda r: {"rows": list(map(set, r)), "cols": list(map(set, zip(*r)))},
+                boards,
+            )
+        )
+        for i in range(5, len(queue)):
+            called = queue[:i]
+            for i, b in enumerate(boards):
+                if any(bingo(called, r) for r in b["rows"]) or any(
+                    bingo(called, c) for c in b["cols"]
+                ):
+                    return called, b["rows"], i
+
+
+if __name__ == "__main__":
+    solution = Solution()
+    solution.show_results()
diff --git a/2021-python/tests/test_day_04.py b/2021-python/tests/test_day_04.py
new file mode 100644
index 0000000..882c64e
--- /dev/null
+++ b/2021-python/tests/test_day_04.py
@@ -0,0 +1,59 @@
+import unittest
+
+from solutions.day_04 import Solution
+
+
+class Day04TestCase(unittest.TestCase):
+    def setUp(self):
+        self.solution = Solution()
+        self.puzzle_input = self.solution.parse_input(
+            """
+        7,4,9,5,11,17,23,2,0,14,21,24,10,16,13,6,15,25,12,22,18,20,8,19,3,26,1
+
+22 13 17 11  0
+ 8  2 23  4 24
+21  9 14 16  7
+ 6 10  3 18  5
+ 1 12 20 15 19
+
+ 3 15  0  2 22
+ 9 18 13 17  5
+19  8  7 25 23
+20 11 10 24  4
+14 21 16 12  6
+
+14 21 17 24  4
+10 16 15  9 19
+18  8 23 26 20
+22 11 13  6  5
+ 2  0 12  3  7
+        """
+        )
+
+    def test_parse_puzzle_input(self):
+        data = """
+        7,4,9
+
+22 13 17 11  0
+ 8  2 23  4 24
+
+ 3 15  0  2 22
+ 9 18 13 17  5
+        """
+        assert self.solution.parse_input(data) == (
+            [7, 4, 9],
+            [
+                [[22, 13, 17, 11, 0], [8, 2, 23, 4, 24]],
+                [[3, 15, 0, 2, 22], [9, 18, 13, 17, 5]],
+            ],
+        )
+
+    def test_solve_first_part(self):
+        assert self.solution.solve(self.puzzle_input) == 188 * 24
+
+    def test_solve_second_part(self):
+        assert self.solution.solve_again(self.puzzle_input) == 148 * 13
+
+
+if __name__ == "__main__":
+    unittest.main()