Merry Christmas?HEADmaster

3 files changed, 79 insertions, 2 deletions

diff --git a/2025/12/a-if-it-was-serious.py b/2025/12/a-if-it-was-serious.py
new file mode 100644
index 0000000..59ffd72
--- /dev/null
+++ b/2025/12/a-if-it-was-serious.py
@@ -0,0 +1,45 @@
+import fileinput
+
+class Present:
+        def __init__(self, lines5):
+                self.baseshape = [line[:-1] for line in lines5[1:4]]
+                self.area = sum(l.count('#') for l in self.baseshape)
+
+        @staticmethod
+        def pretty(s):
+                return '\n'.join(s)
+
+        def __str__(self):
+                return Present.pretty(self.baseshape)
+
+        @staticmethod
+        def singlerot(s):
+                return [''.join(s[j][2-i] for j in range(3)) for i in range(3)]
+
+        @staticmethod
+        def singleflip(s):
+                return [''.join(s[i][2-j] for j in range(3)) for i in range(3)]
+
+        def shape(self, rot, flip):
+                s = list(self.baseshape)
+                for _ in range(rot):
+                        s = Present.singlerot(s)
+                if flip:
+                        s = Present.singleflip(s)
+                return s
+
+class Region:
+        def __init__(self, line):
+                wh, n = line[:-1].split(': ')
+                self.w, self.h = tuple(int(i) for i in wh.split('x'))
+                self.p = [int(i) for i in n.split(' ')]
+
+        def __str__(self):
+                return f"({self.w}x{self.h}) {self.p}"
+
+with fileinput.input() as lines:
+        lines = list(lines)
+        presents = [Present(lines[5*i:5*(i+1)]) for i in range(6)]
+        regions = [Region(line) for line in lines[30:]]
+
+# Then you'd have to find some algorithm to solve this, but it is crazy hard
diff --git a/2025/12/a.py b/2025/12/a.py
index 5fdb11b..cac2c38 100644
--- a/2025/12/a.py
+++ b/2025/12/a.py
@@ -1,6 +1,23 @@
+# Just estimate if the shape fit basd on the area. I feel like I am
+# being pranked, this problem sucks.
+
 import fileinput
 
+def present_area(lines5):
+        return sum(l.count('#') for l in lines5)
+
+def region(line):
+        wh, n = line[:-1].split(': ')
+        wh = tuple(int(i) for i in wh.split('x'))
+        c = [int(i) for i in n.split(' ')]
+        return wh, c
+
+def fits(wh, c, areas):
+        return wh[0]*wh[1] >= sum(c[i] * areas[i] for i in range(6))
+
 with fileinput.input() as lines:
-        for line in lines:
-                ...
+        lines = list(lines)
+        areas = [present_area(lines[5*i:5*(i+1)]) for i in range(6)]
+        regions = [region(line) for line in lines[30:]]
 
+print(sum(1 if fits(*region, areas) else 0 for region in regions))
diff --git a/2025/README.md b/2025/README.md
index 951213c..9dac728 100644
--- a/2025/README.md
+++ b/2025/README.md
@@ -11,6 +11,7 @@ Example
 
 ```
 Day   -Part 1-   -Part 2-
+ 12   00:58:32   00:58:36
  11   00:14:22   00:21:19
  10   00:27:43   11:51:51
   9   00:05:05   02:11:41
@@ -227,3 +228,17 @@ or not we have passed through the two required intermediate nodes.
 
 The paths in part 1 are small enough that memoization is not required,
 but in part 2 we need to cache the intermediate results.
+
+## Day 12: Christmas Tree Farm
+
+This problem is literally a prank, I did not like it. I feel bad for the
+people who actually try to solve it.
+
+The actual problem of trying to fit all the presents optimally is
+impossible. Maybe you can come up with an algorithm that works in theory,
+but it's the kind of thing that won't finish until the starvation of
+the last star in the galaxy or stuff like that.
+
+But you can try some simple heuristics, like: if I could chop the presents
+in 1x1 pieces, would they fit? Of course this condition is only necessary,
+and never sufficient... unless you are being pranked. Like in this case.