From 44ece069148eabce2f4d4cb3ccfb68073f39725f Mon Sep 17 00:00:00 2001
From: Joshua Seigler <joshua@seigler.net>
Date: Fri, 9 Dec 2022 12:29:00 -0500
Subject: [PATCH] day 9, this one was fun

---
 .aocrunner.json     | 12 +++---
 README.md           | 18 ++++-----
 src/day09/README.md |  9 +++++
 src/day09/index.ts  | 94 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 118 insertions(+), 15 deletions(-)
 create mode 100644 src/day09/README.md
 create mode 100644 src/day09/index.ts

diff --git a/.aocrunner.json b/.aocrunner.json
index d01328c..0bfc8b7 100644
--- a/.aocrunner.json
+++ b/.aocrunner.json
@@ -117,16 +117,16 @@
     },
     {
       "part1": {
-        "solved": false,
-        "result": null,
+        "solved": true,
+        "result": "5619",
         "attempts": [],
-        "time": null
+        "time": 12.601053
       },
       "part2": {
-        "solved": false,
-        "result": null,
+        "solved": true,
+        "result": "2376",
         "attempts": [],
-        "time": null
+        "time": 15.009934
       }
     },
     {
diff --git a/README.md b/README.md
index 9207f64..e53b344 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@
 [![Day](https://badgen.net/badge/06/%E2%98%85%E2%98%85/green)](src/day06)
 [![Day](https://badgen.net/badge/07/%E2%98%85%E2%98%85/green)](src/day07)
 [![Day](https://badgen.net/badge/08/%E2%98%85%E2%98%85/green)](src/day08)
-![Day](https://badgen.net/badge/09/%E2%98%86%E2%98%86/gray)
+[![Day](https://badgen.net/badge/09/%E2%98%85%E2%98%85/green)](src/day09)
 ![Day](https://badgen.net/badge/10/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/11/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/12/%E2%98%86%E2%98%86/gray)
@@ -118,16 +118,16 @@ Both parts: 2.9718489999999997ms
 
 ```
 Day 08
-Time part 1: 7.541ms
-Time part 2: 8.005ms
-Both parts: 15.545933000000002ms
+Time part 1: 8.863ms
+Time part 2: 8.313ms
+Both parts: 17.175474ms
 ```
 
 ```
 Day 09
-Time part 1: -
-Time part 2: -
-Both parts: -
+Time part 1: 12.601ms
+Time part 2: 15.01ms
+Both parts: 27.610987ms
 ```
 
 ```
@@ -243,8 +243,8 @@ Both parts: -
 ```
 
 ```
-Total stars: 16/50
-Total time: 39.454ms
+Total stars: 18/50
+Total time: 68.695ms
 ```
 
 <!--/RESULTS-->
diff --git a/src/day09/README.md b/src/day09/README.md
new file mode 100644
index 0000000..ba7b5f6
--- /dev/null
+++ b/src/day09/README.md
@@ -0,0 +1,9 @@
+# 🎄 Advent of Code 2022 - day 9 🎄
+
+## Info
+
+Task description: [link](https://adventofcode.com/2022/day/9)
+
+## Notes
+
+...
\ No newline at end of file
diff --git a/src/day09/index.ts b/src/day09/index.ts
new file mode 100644
index 0000000..edb73bf
--- /dev/null
+++ b/src/day09/index.ts
@@ -0,0 +1,94 @@
+import run from "aocrunner"
+
+type directionType = "R" | "L" | "D" | "U"
+const parseInput = (rawInput: string) =>
+  rawInput.split("\n").map((x) => x.split(" ") as [directionType, number])
+
+const deltas = {
+  // row, col
+  R: [0, 1],
+  L: [0, -1],
+  D: [1, 0],
+  U: [-1, 0],
+}
+
+const part1 = (rawInput: string) => {
+  const input = parseInput(rawInput)
+  let h = [0, 0]
+  let t = [0, 0]
+  const visited = new Set(["0/0"])
+
+  for (const [direction, steps] of input) {
+    for (let i = 0; i < steps; i++) {
+      h = [h[0] + deltas[direction][0], h[1] + deltas[direction][1]]
+      const dr = t[0] - h[0]
+      const dc = t[1] - h[1]
+      if (Math.abs(dr) > 1 || Math.abs(dc) > 1) {
+        t[0] -= Math.sign(dr)
+        t[1] -= Math.sign(dc)
+      }
+      visited.add(t.join("/"))
+    }
+  }
+  return visited.size
+}
+
+const part2 = (rawInput: string) => {
+  const input = parseInput(rawInput)
+  const rope = new Array(10).fill(0).map((x) => [0, 0])
+  const visited = new Set(["0/0"])
+
+  for (const [direction, steps] of input) {
+    for (let i = 0; i < steps; i++) {
+      rope[0][0] += deltas[direction][0]
+      rope[0][1] += deltas[direction][1]
+      for (let s = 1; s < rope.length; s++) {
+        const dr = rope[s][0] - rope[s - 1][0]
+        const dc = rope[s][1] - rope[s - 1][1]
+        if (Math.abs(dr) > 1 || Math.abs(dc) > 1) {
+          rope[s][0] -= Math.sign(dr)
+          rope[s][1] -= Math.sign(dc)
+        }
+      }
+      visited.add(rope.at(-1)!.join("/"))
+    }
+  }
+  return visited.size
+}
+
+run({
+  part1: {
+    tests: [
+      {
+        input: `R 4
+U 4
+L 3
+D 1
+R 4
+D 1
+L 5
+R 2`,
+        expected: 13,
+      },
+    ],
+    solution: part1,
+  },
+  part2: {
+    tests: [
+      {
+        input: `R 5
+U 8
+L 8
+D 3
+R 17
+D 10
+L 25
+U 20`,
+        expected: 36,
+      },
+    ],
+    solution: part2,
+  },
+  trimTestInputs: true,
+  onlyTests: false,
+})