From 8777ff071f7bb37631baa7b6717ad29961e50911 Mon Sep 17 00:00:00 2001
From: "H.J" <thechairman@thechairman.info>
Date: Wed, 9 Oct 2024 11:36:55 -0400
Subject: sorting by language

---
 racket/aoc2022/day-06/day-06.ipynb | 122 +++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 racket/aoc2022/day-06/day-06.ipynb

(limited to 'racket/aoc2022/day-06/day-06.ipynb')

diff --git a/racket/aoc2022/day-06/day-06.ipynb b/racket/aoc2022/day-06/day-06.ipynb
new file mode 100644
index 0000000..0c89fa1
--- /dev/null
+++ b/racket/aoc2022/day-06/day-06.ipynb
@@ -0,0 +1,122 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Advent of Code 2022\n",
+    "#### Day 6: Tuning Trouble\n",
+    "\n",
+    "You're parsing a buffer of characters, looking for a \"marker\": the index of the first character where the previous $n$ characters are all unique.\n",
+    "\n",
+    "**Part 1.** What if $n = 4$, for the \"start of packet\" marker?\n",
+    "\n",
+    "**Part 2.** What if $n = 14$, for the \"start of message\" marker?"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "(require racket\n",
+    "         advent-of-code\n",
+    "         (only-in algorithms sliding))\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "##### Parts 1 and 2\n",
+    "\n",
+    "`(sliding xs n)` returns all the overlapping sublists of `xs` that are `n` elements wide.  This turns this problem into a simple `for` comprehension, just looking for the first sublist with no duplicates (which means its length after deduplication doesn't change).\n",
+    "\n",
+    "The solution to part 1 and part 2 is the same, just differing in how wide the window is."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<code>1042</code>"
+      ],
+      "text/plain": [
+       "1042"
+      ]
+     },
+     "execution_count": 2,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "(define buffer (fetch-aoc-input (find-session) 2022 6))\n",
+    "\n",
+    "(define (find-marker data type)\n",
+    "  (define n\n",
+    "    (match type\n",
+    "      ['start-of-packet 4]\n",
+    "      ['start-of-message 14]))\n",
+    "  (for/first ([chunk (in-list (sliding (string->list data) n))]\n",
+    "              [i (in-naturals n)]\n",
+    "              #:when (= n (~> chunk remove-duplicates length)))\n",
+    "    i))\n",
+    "\n",
+    "(find-marker buffer 'start-of-packet)\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/html": [
+       "<code>2980</code>"
+      ],
+      "text/plain": [
+       "2980"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "(find-marker buffer 'start-of-message)"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Racket (trusted)",
+   "language": "racket",
+   "name": "racket-trusted"
+  },
+  "language_info": {
+   "codemirror_mode": "scheme",
+   "file_extension": ".rkt",
+   "mimetype": "text/x-racket",
+   "name": "racket",
+   "pygments_lexer": "racket",
+   "version": "8.7"
+  },
+  "orig_nbformat": 4,
+  "vscode": {
+   "interpreter": {
+    "hash": "916dbcbb3f70747c44a77c7bcd40155683ae19c65e1c03b4aa3499c5328201f1"
+   }
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}
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