day 8

.aocrunner.json

@@ -107,16 +107,21 @@
     },
     {
       "part1": {
-        "solved": false,
-        "result": null,
-        "attempts": [],
-        "time": null
+        "solved": true,
+        "result": "390",
+        "attempts": [
+          "403"
+        ],
+        "time": 0.758513
       },
       "part2": {
-        "solved": false,
-        "result": null,
-        "attempts": [],
-        "time": null
+        "solved": true,
+        "result": "1246",
+        "attempts": [
+          "1188",
+          "1177"
+        ],
+        "time": 1.104361
       }
     },
     {

README.md

@@ -18,7 +18,7 @@
 [![Day](https://badgen.net/badge/05/%E2%98%85%E2%98%85/green)](src/day05)
 [![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%86%E2%98%86/gray)
+[![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/10/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/11/%E2%98%86%E2%98%86/gray)
@@ -111,16 +111,16 @@ Both parts: 37138.281ms
 
 ```
 Day 07
-Time part 1: 21.473ms
-Time part 2: 782.405ms
-Both parts: 803.878ms
+Time part 1: 23.012ms
+Time part 2: 599.069ms
+Both parts: 622.08ms
 ```
 
 ```
 Day 08
-Time part 1: -
-Time part 2: -
-Both parts: -
+Time part 1: 0.759ms
+Time part 2: 1.104ms
+Both parts: 1.863ms
 ```
 
 ```
@@ -243,8 +243,8 @@ Both parts: -
 ```
 
 ```
-Total stars: 14/50
-Total time: 38264.809ms
+Total stars: 16/50
+Total time: 38084.874ms
 ```
 
 <!--/RESULTS-->

src/day08/README.md

@@ -0,0 +1,9 @@
+# 🎄 Advent of Code 2024 - day 8 🎄
+
+## Info
+
+Task description: [link](https://adventofcode.com/2024/day/8)
+
+## Notes
+
+...

src/day08/index.ts

@@ -0,0 +1,128 @@
+import run from "aocrunner"
+
+const parseInput = (rawInput: string) => rawInput.split('\n').map(line => line.split(''))
+
+const part1 = (rawInput: string) => {
+  const rows = parseInput(rawInput)
+  const towers = new Map<string, string[]>() // 'a' => ['4,5', '7,7'] etc
+  const antinodes = new Set<string>()
+  rows.forEach((row, r) => {
+    row.forEach((char, c) => {
+      if (char === '.') return
+      const towerLocations = towers.get(char) ?? []
+      towerLocations.forEach(locationKey => {
+        const [r2,c2] = locationKey.split(',').map(Number)
+        const newAntinodes = [[2*r2-r, 2*c2-c], [2*r-r2, 2*c-c2]]
+        newAntinodes.forEach(([y, x]) => {
+          if (y < 0 || y >= rows.length || x < 0 || x >= row.length) {
+            return
+          }
+          antinodes.add(`${y},${x}`)
+        })
+      })
+      towerLocations.push(`${r},${c}`)
+      towers.set(char, towerLocations)
+    })
+  })
+  return antinodes.size
+}
+
+const part2 = (rawInput: string) => {
+  const rows = parseInput(rawInput)
+  const towers = new Map<string, string[]>() // 'a' => ['4,5', '7,7'] etc
+  const antinodes = new Set<string>()
+  rows.forEach((row, r) => {
+    row.forEach((char, c) => {
+      if (char === '.') return
+      const towerLocations = towers.get(char) ?? []
+      towerLocations.forEach(locationKey => {
+        const [r2,c2] = locationKey.split(',').map(Number)
+        const slopeTop = c2-c
+        const slopeBottom = r2-r
+        for (let R = 0; R < rows.length; R++) {
+          const dr = R - r
+          const dc = dr * slopeTop / slopeBottom
+          const C = c + dc
+          if (C < 0 || C >= row.length || C % 1 !== 0) {
+            continue
+          }
+          antinodes.add(`${R},${C}`)
+        }
+      })
+      towerLocations.push(`${r},${c}`)
+      towers.set(char, towerLocations)
+    })
+  })
+  return antinodes.size
+}
+
+run({
+  part1: {
+    tests: [
+      {
+        input: `..........
+..........
+..........
+....a.....
+........a.
+.....a....
+..........
+..........
+..........
+..........`,
+        expected: 4
+      },
+      {
+        input: `............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............`,
+        expected: 14,
+      },
+    ],
+    solution: part1,
+  },
+  part2: {
+    tests: [
+      {
+        input: `T.........
+...T......
+.T........
+..........
+..........
+..........
+..........
+..........
+..........
+..........`,
+        expected: 9
+      },
+      {
+        input: `............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............`,
+        expected: 34,
+      },
+    ],
+    solution: part2,
+  },
+  trimTestInputs: true,
+  onlyTests: false,
+})