From a7711439913ca8987d61d8e5bc9181e54c1fcd1b Mon Sep 17 00:00:00 2001
From: Joshua Seigler <joshua@seigler.net>
Date: Mon, 6 Dec 2021 01:15:32 -0500
Subject: [PATCH] day 6

---
 .aocrunner.json     | 12 ++++++------
 README.md           | 12 ++++++------
 src/day06/README.md |  9 +++++++++
 src/day06/index.js  | 42 ++++++++++++++++++++++++++++++++++++++++++
 src/utils/index.js  | 21 +++++++++++++++++++++
 5 files changed, 84 insertions(+), 12 deletions(-)
 create mode 100644 src/day06/README.md
 create mode 100644 src/day06/index.js

diff --git a/.aocrunner.json b/.aocrunner.json
index a543e98..aa06d85 100644
--- a/.aocrunner.json
+++ b/.aocrunner.json
@@ -81,16 +81,16 @@
     },
     {
       "part1": {
-        "solved": false,
-        "result": null,
+        "solved": true,
+        "result": "386755",
         "attempts": [],
-        "time": null
+        "time": 24.88
       },
       "part2": {
-        "solved": false,
-        "result": null,
+        "solved": true,
+        "result": "1732731810807",
         "attempts": [],
-        "time": null
+        "time": 0.2
       }
     },
     {
diff --git a/README.md b/README.md
index c42eea2..6e82c40 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@
 [![Day](https://badgen.net/badge/03/%E2%98%85%E2%98%85/green)](src/day03)
 [![Day](https://badgen.net/badge/04/%E2%98%85%E2%98%85/green)](src/day04)
 [![Day](https://badgen.net/badge/05/%E2%98%85%E2%98%85/green)](src/day05)
-![Day](https://badgen.net/badge/06/%E2%98%86%E2%98%86/gray)
+[![Day](https://badgen.net/badge/06/%E2%98%85%E2%98%85/green)](src/day06)
 ![Day](https://badgen.net/badge/07/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/08/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/09/%E2%98%86%E2%98%86/gray)
@@ -104,9 +104,9 @@ Both parts: 217.70999999999998ms
 
 ```
 Day 06
-Time part 1: -
-Time part 2: -
-Both parts: -
+Time part 1: 24.88ms
+Time part 2: 0.2ms
+Both parts: 25.08ms
 ```
 
 ```
@@ -243,8 +243,8 @@ Both parts: -
 ```
 
 ```
-Total stars: 10/50
-Total time: 306.71ms
+Total stars: 12/50
+Total time: 331.78999999999996ms
 ```
 
 <!--/RESULTS-->
diff --git a/src/day06/README.md b/src/day06/README.md
new file mode 100644
index 0000000..98bb6d8
--- /dev/null
+++ b/src/day06/README.md
@@ -0,0 +1,9 @@
+# 🎄 Advent of Code 2021 - day 6 🎄
+
+## Info
+
+Task description: [link](https://adventofcode.com/2021/day/6)
+
+## Notes
+
+...
\ No newline at end of file
diff --git a/src/day06/index.js b/src/day06/index.js
new file mode 100644
index 0000000..2b6e14e
--- /dev/null
+++ b/src/day06/index.js
@@ -0,0 +1,42 @@
+import run from "aocrunner"
+import { memo } from "../utils/index.js"
+
+const parseInput = (rawInput) => rawInput.trim().split`,`.map((x) => +x)
+
+const part1 = (rawInput) => {
+  const input = parseInput(rawInput)
+  for (let i = 0; i < 80; i++) {
+    const length = input.length
+    for (let j = 0; j < length; j++) {
+      if (input[j]-- === 0) {
+        input[j] = 6
+        input.push(8)
+      }
+    }
+  }
+  return input.length
+}
+
+const part2 = (rawInput) => {
+  const input = parseInput(rawInput)
+  const bins = new Array(9).fill(0)
+  input.forEach((f) => bins[f]++)
+  for (let i = 0; i < 256; i++) {
+    const spawning = bins.shift()
+    bins.push(spawning)
+    bins[6] += spawning
+  }
+  return bins.reduce((acc, x) => acc + x, 0)
+}
+
+run({
+  part1: {
+    tests: [{ input: `3,4,3,1,2`, expected: 5934 }],
+    solution: part1,
+  },
+  part2: {
+    tests: [{ input: `3,4,3,1,2`, expected: 26984457539 }],
+    solution: part2,
+  },
+  trimTestInputs: true,
+})
diff --git a/src/utils/index.js b/src/utils/index.js
index 6619010..9a139fc 100644
--- a/src/utils/index.js
+++ b/src/utils/index.js
@@ -34,3 +34,24 @@ export function sequence(a, b) {
   }
   return s
 }
+
+export function memo(fn) {
+  const cache = {}
+
+  function get(args) {
+    let node = cache
+    for (const arg of args) {
+      if (!("next" in node)) node.next = new Map()
+      if (!node.next.has(arg)) node.next.set(arg, {})
+      node = node.next.get(arg)
+    }
+    return node
+  }
+
+  return function (...args) {
+    const cache = get(args)
+    if ("item" in cache) return cache.item
+    cache.item = fn(...args)
+    return cache.item
+  }
+}