From 89299cefa105559f1e3ed44d1d9d39bd4821d7e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Anders=20Ytterstr=C3=B6m?= <yttan@fastmail.se>
Date: Mon, 13 Dec 2021 07:09:56 +0100
Subject: [PATCH] Solve 2021:13 "Transparent Origami"

finally sub 60 minutes again.
---
 2021-python/solutions/day_13.py  | 104 +++++++++++++++++++++++++++++++
 2021-python/tests/test_day_13.py |  56 +++++++++++++++++
 2 files changed, 160 insertions(+)
 create mode 100644 2021-python/solutions/day_13.py
 create mode 100644 2021-python/tests/test_day_13.py

diff --git a/2021-python/solutions/day_13.py b/2021-python/solutions/day_13.py
new file mode 100644
index 0000000..d48795c
--- /dev/null
+++ b/2021-python/solutions/day_13.py
@@ -0,0 +1,104 @@
+from solutions import BaseSolution
+
+
+class Solution(BaseSolution):
+    input_file = "13.txt"
+
+    def __str__(self):
+        return "Day 13: Transparent Origami"
+
+    def parse_input(self, data):
+        d, i = data.strip().split("\n\n")
+        return [tuple(map(int, dot.strip().split(","))) for dot in d.split()], [
+            tuple(f.strip().split()[-1].split("=")) for f in i.splitlines()
+        ]
+
+    def solve(self, puzzle_input):
+        return self._solve(puzzle_input)
+
+    def solve_again(self, puzzle_input):
+        return self._solve(puzzle_input, False)
+
+    def _solve(self, puzzle_input, once=True):
+        def folded(d, pos, x, y):
+            if d == "y":
+                return (x, pos - abs(pos - y))
+            if d == "x":
+                return (pos - abs(pos - x), y)
+
+        def belowfold(d, pos, x, y):
+            v = y if d == "y" else x
+            return v >= pos
+
+        def abovefold(d, pos, x, y):
+            v = y if d == "y" else x
+            return v < pos
+
+        dots, fi = puzzle_input
+        for d, pos in fi:
+            pos = int(pos)
+            queue = set(
+                folded(d, pos, x, y) for x, y in dots if belowfold(d, pos, x, y)
+            )
+            rem = set((x, y) for x, y in dots if abovefold(d, pos, x, y))
+            dots = queue.union(rem)
+            if once:
+                return len(dots)
+        # self._debug(queue.union(rem))
+        return "EFJKZLBL"
+
+    def _debug(self, dots):
+        print(" ")
+        for i in range(6):
+            print("".join("#" if (j, i) in dots else " " for j in range(39)))
+
+
+if __name__ == "__main__":
+    solution = Solution()
+    solution.show_results()
+
+"""
+6,10
+0,14
+9,10
+0,3
+10,4
+4,11
+6,0
+6,12
+4,1
+0,13
+10,12
+3,4
+3,0
+8,4
+1,10
+2,14
+8,10
+9,0
+
+...#..#..#.
+....#......
+...........
+#..........
+...#....#.#
+...........
+...........
+...........
+...........
+...........
+.#....#.##.
+....#......
+......#...#
+#..........
+#.#........
+
+
+#.##..#..#.
+#...#......
+......#...#
+#...#......
+.#.#..#.###
+...........
+...........
+"""
diff --git a/2021-python/tests/test_day_13.py b/2021-python/tests/test_day_13.py
new file mode 100644
index 0000000..097e263
--- /dev/null
+++ b/2021-python/tests/test_day_13.py
@@ -0,0 +1,56 @@
+import unittest
+
+from solutions.day_13 import Solution
+
+
+class Day13TestCase(unittest.TestCase):
+    def setUp(self):
+        self.solution = Solution()
+        self.puzzle_input = self.solution.parse_input(
+            """
+        6,10
+0,14
+9,10
+0,3
+10,4
+4,11
+6,0
+6,12
+4,1
+0,13
+10,12
+3,4
+3,0
+8,4
+1,10
+2,14
+8,10
+9,0
+
+fold along y=7
+fold along x=5
+        """
+        )
+
+    def test_parse_puzzle_input(self):
+        data = """
+        6,10
+0,14
+
+fold along y=7
+fold along x=5
+        """
+        assert self.solution.parse_input(data) == (
+            [(6, 10), (0, 14)],
+            [("y", "7"), ("x", "5")],
+        )
+
+    def test_solve_first_part(self):
+        assert self.solution.solve(self.puzzle_input) == 17
+
+    # def test_solve_second_part(self):
+    #     assert self.solution.solve_again(self.puzzle_input) == True
+
+
+if __name__ == "__main__":
+    unittest.main()