day 10

.aocrunner.json

@@ -145,16 +145,16 @@
     },
     {
       "part1": {
-        "solved": false,
-        "result": null,
+        "solved": true,
+        "result": "782",
         "attempts": [],
-        "time": null
+        "time": 6.147158
       },
       "part2": {
-        "solved": false,
-        "result": null,
+        "solved": true,
+        "result": "1694",
         "attempts": [],
-        "time": null
+        "time": 4.868614
       }
     },
     {

README.md

@@ -20,7 +20,7 @@
 [![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%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/10/%E2%98%85%E2%98%85/green)](src/day10)
 ![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)
 ![Day](https://badgen.net/badge/13/%E2%98%86%E2%98%86/gray)
@@ -125,16 +125,16 @@ Both parts: 1.863ms
 
 ```
 Day 09
-Time part 1: 239.635ms
-Time part 2: 53.494ms
-Both parts: 293.129ms
+Time part 1: 236.521ms
+Time part 2: 51.928ms
+Both parts: 288.449ms
 ```
 
 ```
 Day 10
-Time part 1: -
-Time part 2: -
-Both parts: -
+Time part 1: 6.148ms
+Time part 2: 4.028ms
+Both parts: 10.176ms
 ```
 
 ```
@@ -243,8 +243,8 @@ Both parts: -
 ```
 
 ```
-Total stars: 18/50
-Total time: 38378.002ms
+Total stars: 20/50
+Total time: 38383.499ms
 ```
 
 <!--/RESULTS-->

src/day10/README.md

@@ -0,0 +1,9 @@
+# 🎄 Advent of Code 2024 - day 10 🎄
+
+## Info
+
+Task description: [link](https://adventofcode.com/2024/day/10)
+
+## Notes
+
+...

src/day10/index.ts

@@ -0,0 +1,136 @@
+import run from "aocrunner"
+
+const parseInput = (rawInput: string) => rawInput.split('\n').map(line => line.split('').map(Number))
+
+const directions = [
+  [-1, 0], // up
+  [0, 1], // right
+  [1, 0], // down
+  [0, -1] // left
+]
+
+const sum = (a,b) => a + b
+
+const getKey = (r: number, c: number) => `${r},${c}`
+type Key = ReturnType<typeof getKey>
+
+const part1 = (rawInput: string) => {
+  const input = parseInput(rawInput)
+  const trailheads: Key[] = []
+  const exitsMap = new Map<Key, Key[]>()
+  const get = (r: number, c: number) => {
+    return (input[r] ?? [])[c]
+  }
+  input.forEach((row, r) => {
+    row.forEach((alt, c) => {
+      const key = getKey(r, c)
+      if (alt === 0) {
+        trailheads.push(key)
+      }
+      const outs: Key[] = []
+      directions.forEach(([dr, dc]) => {
+        if (get(r + dr, c + dc) === alt + 1) {
+          outs.push(getKey(r + dr, c + dc))
+        }
+      })
+      exitsMap.set(key, outs)
+    })
+  })
+  const reachablePeaks = new Map<Key, Set<Key>>()
+  const hike = (key: Key, alt: number = 0): Set<Key> => {
+    let ans = reachablePeaks.get(key)
+    if (ans !== undefined) return ans
+    ans = new Set<Key>()
+    if (alt === 9) {
+      ans.add(key)
+      reachablePeaks.set(key, ans)
+      return ans
+    }
+    const branches = (exitsMap.get(key) ?? []).map(k => hike(k,alt+1))
+    branches.forEach(peaks => {
+      peaks.forEach(peak => ans.add(peak))
+    })
+    reachablePeaks.set(key, ans)
+    return ans
+  }
+  return trailheads.map(t => hike(t).size).reduce(sum, 0)
+}
+
+const part2 = (rawInput: string) => {
+  const input = parseInput(rawInput)
+  const trailheads: Key[] = []
+  const exitsMap = new Map<Key, Key[]>()
+  const get = (r: number, c: number) => {
+    return (input[r] ?? [])[c]
+  }
+  input.forEach((row, r) => {
+    row.forEach((alt, c) => {
+      const key = getKey(r, c)
+      if (alt === 0) {
+        trailheads.push(key)
+      }
+      const outs: Key[] = []
+      directions.forEach(([dr, dc]) => {
+        if (get(r + dr, c + dc) === alt + 1) {
+          outs.push(getKey(r + dr, c + dc))
+        }
+      })
+      exitsMap.set(key, outs)
+    })
+  })
+  const cache = new Map<Key, number>()
+  const hike = (key: Key, alt: number): number => {
+    if (alt === 9) {
+      return 1
+    }
+    let ans = cache.get(key)
+    if (ans !== undefined) return ans
+    const exitTotals = (exitsMap.get(key) ?? []).map(k => hike(k,alt+1))
+    ans = exitTotals.reduce(sum, 0)
+    cache.set(key, ans)
+    return ans
+  }
+  return trailheads.map(t => hike(t,0)).reduce(sum, 0)
+}
+
+run({
+  part1: {
+    tests: [
+      {
+        input: `0123
+1234
+8765
+9876`,
+        expected: 1,
+      },
+    ],
+    solution: part1,
+  },
+  part2: {
+    tests: [
+      {
+        input: `012345
+123456
+234567
+345678
+4.6789
+56789.`,
+expected: 227
+      },
+      {
+        input: `89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732`,
+        expected: 81,
+      },
+    ],
+    solution: part2,
+  },
+  trimTestInputs: true,
+  onlyTests: false,
+})