day 13

2021/13/README.md

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+# 13
+
+Ahh, RTFM! I did not get what was wrong. You are supposed to only input the first fold for the first question.
+
+Second part is a joy :) I already had the "screen" working, so that was an easy fix win.
+
+<details>
+  <summary>Solutions</summary>
+  <ol>
+    <li>807</li>
+    <li>2</li>
+  </ol>
+</details>

2021/13/python/main.py

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+#!/usr/bin/env python
+
+from os.path import dirname, join
+from typing import Tuple
+
+# Day 13
+
+# Common
+
+
+def read_input(filename):
+    data = join(dirname(__file__), '..', filename)
+    with open(data) as f:
+        return f.read().strip()
+
+
+test = read_input('test.txt')
+data = read_input('input.txt')
+
+
+class Paper:
+    def __init__(self, points: set[tuple[int, int]], folds=list[tuple[bool, int]]):
+        self.points = points
+        self.folds = folds
+
+    def __str__(self):
+        max_x = 0
+        max_y = 0
+        for x, y in self.points:
+            max_x = max(max_x, x)
+            max_y = max(max_y, y)
+
+        # Init grid
+        grid = [
+            ['.' for _ in range(max_x+1)]
+            for _ in range(max_y+1)
+        ]
+
+        # Fill grid
+        for x, y in self.points:
+            grid[y][x] = '#'
+
+        return '\n'.join([
+            ''.join(row)
+            for row in grid
+        ])
+
+    def fold_all(self):
+        for fold in self.folds:
+            self.fold(fold)
+
+    def fold(self, fold):
+        x, threshold = fold
+        i = 0 if x else 1
+        for point in list(self.points):
+            value = point[i]
+            if value < threshold:
+                continue
+            new_value = 2*threshold - value
+            self.points.remove(point)
+            p = list(point)
+            p[i] = new_value
+            self.points.add(tuple(p))
+
+    def flag_1(self):
+        self.fold(self.folds[0])
+        print(len(self.points))
+
+    def flag_2(self):
+        self.fold_all()
+        print(self)
+
+    @staticmethod
+    def parse(data: str) -> 'Paper':
+        header, footer = data.split('\n\n')
+        points = {
+            tuple(map(int, point.split(',')))
+            for point
+            in header.split('\n')
+        }
+
+        folds = [
+            (fold[11] == 'x', int(fold[13:]))
+            for fold in footer.split('\n')
+        ]
+        return Paper(points, folds)
+
+        # 1
+print('1.')
+paper = Paper.parse(test)
+paper.flag_1()
+paper = Paper.parse(data)
+paper.flag_1()
+
+
+# 2
+print('\n2.')
+paper = Paper.parse(test)
+paper.flag_2()
+paper = Paper.parse(data)
+paper.flag_2()