From 8910705d2e9686b0572243e8b19455996f302532 Mon Sep 17 00:00:00 2001
From: Stefan Harmuth <pennywise@drock.de>
Date: Tue, 9 Jan 2024 08:46:38 +0100
Subject: [PATCH] Day 21 - some fiddling around

---
 day21.py | 68 ++++++++++++++++++++++++++++++--------------------------
 1 file changed, 36 insertions(+), 32 deletions(-)

diff --git a/day21.py b/day21.py
index 28f1671..24347ac 100644
--- a/day21.py
+++ b/day21.py
@@ -1,7 +1,9 @@
+import math
 from collections import deque, defaultdict
 from tools.aoc import AOCDay
-from tools.coordinate import Coordinate
+from tools.coordinate import Coordinate, Line
 from tools.grid import Grid
+from tools.visualization import Window
 from typing import Any
 
 
@@ -13,23 +15,23 @@ def walk(grid: Grid, start: Coordinate, steps: int) -> int:
     v2 = set()
     while q:
         coord, dist = q.popleft()
-        #print("check ", coord, dist)
+        # print("check ", coord, dist)
         if coord in v or coord in v2:
-            #print(" -> in v")
+            # print(" -> in v")
             continue
         if dist % 2 == s_mod:
-            #print(f" -> add to v because {dist} even or == {steps}")
+            # print(f" -> add to v because {dist} even or == {steps}")
             v.add(coord)
         else:
             v2.add(coord)
         if dist >= steps:
-            #print(f" -> >= {steps}")
+            # print(f" -> >= {steps}")
             continue
         for n in coord.getNeighbours(includeDiagonal=False):
             if grid.get(n % (grid.maxX + 1)):
                 q.append((n, dist + 1))
 
-    #print([x for x in v])
+    # print([x for x in v])
     return len(v)
 
 
@@ -40,48 +42,50 @@ class Day(AOCDay):
             (3562, "input21"),
         ],
         [
-            #(16733044, "input21_test"),
+            # (16733044, "input21_test"),
             (None, "input21"),
-        ]
+        ],
     ]
 
     def parse_input(self) -> (Grid, Coordinate):
-        grid = Grid().from_data(self.getInput(), translate={'.': True, '#': False})
+        grid = Grid().from_data(self.getInput(), translate={".": True, "#": False})
         start = None
-        for x in grid.getActiveCells():
-            if grid.get(x) == 'S':
-                start = x
-                grid.set(x, True)
+        for x in grid.find("S"):
+            start = x
+            grid.set(x, True)
+            break  # there is only one S
 
         return grid, start
 
     def part1(self) -> Any:
-        needed_steps = 6 if 'test' in self._current_test_file else 64
+        needed_steps = 6 if self.is_test() else 64
         grid, start = self.parse_input()
         return walk(grid, start, needed_steps)
 
     def part2(self) -> Any:
         grid, start = self.parse_input()
-        needed_steps = 5000 if 'test' in self._current_test_file else 26501365
-        k = walk(grid, start, len(self.getInput()))
-        g = walk(grid, start, 2 * len(self.getInput()))
-        v = walk(grid, start, 3 * len(self.getInput()))
-        print(k, g, v, g-k, v-g)
-        return ""
-        j = 0
-        mem = defaultdict(list)
-        for i in range(1, 250, 2):
-            k = walk(grid, start, i)
-            diff = k - j
-            j = k
-            mem[diff].append(i)
-            print(i, "=>", k, "diff", diff, "mod", k % 81)
-        for k, v in mem.items():
-            if len(v) > 1:
-                print(k, "=>", v)
+        print(grid.getOnCount())
+        for i in [Coordinate(0, 65), Coordinate(65, 0), Coordinate(130, 65), Coordinate(65, 130)]:
+            t = walk(grid, i, 131)  # this always yields 14746 ... coincidence?
+            print(f"{i} = {t}")
+
+        for i in [Coordinate(0, 0), Coordinate(130, 0), Coordinate(0, 130), Coordinate(130, 130)]:
+            t = walk(grid, i, 65)
+            print(f"{i} = {t}")
+        needed_steps = 5000 if self.is_test() else 26501365
+        t = walk(grid, start, 64)
+        k = walk(grid, start, len(self.getInput()) + 65)
+        g = walk(grid, start, 2 * len(self.getInput()) + 65)
+        # v = walk(grid, start, (3 * len(self.getInput())) - 1)
+        print(f"65={t}, 196={k}, 327={g}, {math.log(k)=}, {math.log(g)=}")
+        print(((k - t) / 14746) * 3)
+        print((g - t) / 14746)
+        print((g - k) / 14746)
+        print(g % k)
+        print(k / t)
         return ""
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     day = Day(2023, 21)
     day.run(verbose=True)