day 12 part 2 fixed

.aocrunner.json

@@ -183,10 +183,10 @@
         "time": null
       },
       "part2": {
-        "solved": false,
+        "solved": true,
-        "result": null,
+        "result": "904114",
         "attempts": [],
-        "time": null
+        "time": 220.713667
       }
     },
     {

README.md

@@ -22,7 +22,7 @@
 [![Day](https://badgen.net/badge/09/%E2%98%85%E2%98%85/green)](src/day09)
 [![Day](https://badgen.net/badge/10/%E2%98%85%E2%98%85/green)](src/day10)
 [![Day](https://badgen.net/badge/11/%E2%98%85%E2%98%85/green)](src/day11)
-[![Day](https://badgen.net/badge/12/%E2%98%85%E2%98%86/yellow)](src/day12)
+[![Day](https://badgen.net/badge/12/%E2%98%85%E2%98%85/green)](src/day12)
 ![Day](https://badgen.net/badge/13/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/14/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/15/%E2%98%86%E2%98%86/gray)
@@ -146,9 +146,9 @@ Both parts: 130.69ms
 
 ```
 Day 12
-Time part 1: 197.261ms
+Time part 1: -
-Time part 2: -
+Time part 2: 220.714ms
-Both parts: 197.261ms
+Both parts: 220.714ms
 ```
 
 ```
@@ -243,8 +243,8 @@ Both parts: -
 ```
 
 ```
-Total stars: 23/50
+Total stars: 24/50
-Total time: 38712.29ms
+Total time: 38735.743ms
 ```
 
 <!--/RESULTS-->

src/day12/index.ts

@@ -1,19 +1,26 @@
 import run from "aocrunner"
 
-const parseInput = (rawInput: string) => rawInput.split('\n').map(line => line.split(''))
+const parseInput = (rawInput: string) =>
+  rawInput.split("\n").map((line) => line.split(""))
 
-const directions = [
+const orthogonals = [
   [-1, 0], // up
   [0, 1], // right
   [1, 0], // down
-  [0, -1] // left
+  [0, -1], // left
+]
+const diagonals = [
+  [-1, 1], // up right
+  [1, 1], // down right
+  [1, -1], // down left
+  [-1, -1], // up left
 ]
 const getNeighbors = (r: number, c: number) => {
-  return directions.map(([dr, dc]) => [r + dr, c + dc])
+  return orthogonals.map(([dr, dc]) => [r + dr, c + dc])
 }
 
 const getKey = (items: unknown[]) => {
-  return items.join(',')
+  return items.join(",")
 }
 type Key = ReturnType<typeof getKey>
 
@@ -34,30 +41,38 @@ const part1 = (rawInput: string) => {
       const neighbors = getNeighbors(r, c).map(getKey)
       let touches = 0
       let matchingRegions: Region[] = []
-      regions.forEach(region => {
+      regions.forEach((region) => {
         if (region.symbol !== symbol) return
-        const newTouches = region.plots.filter(c => neighbors.includes(c)).length
+        const newTouches = region.plots.filter((c) =>
+          neighbors.includes(c),
+        ).length
         if (newTouches > 0) {
           touches += newTouches
           matchingRegions.push(region)
           regions.delete(region)
         }
       })
-      const newRegion = matchingRegions.reduce<Region>((acc, cur) => {
+      const newRegion = matchingRegions.reduce<Region>(
+        (acc, cur) => {
           acc.area += cur.area
           acc.perimeter += cur.perimeter
           acc.plots.push(...cur.plots)
           return acc
-      }, {
+        },
+        {
           symbol,
           area: 1,
           perimeter: 4 - 2 * touches,
           plots: [key],
-      })
+        },
+      )
       regions.add(newRegion)
     })
   })
-  return Array.from(regions).reduce((total, region) => total + region.perimeter * region.area, 0)
+  return Array.from(regions).reduce(
+    (total, region) => total + region.perimeter * region.area,
+    0,
+  )
 }
 
 const part2 = (rawInput: string) => {
@@ -70,58 +85,60 @@ const part2 = (rawInput: string) => {
       const neighbors = getNeighbors(r, c).map(getKey)
       let touches = 0
       let matchingRegions: Region[] = []
-      regions.forEach(region => {
+      regions.forEach((region) => {
         if (region.symbol !== symbol) return
-        const newTouches = region.plots.filter(c => neighbors.includes(c)).length
+        const newTouches = region.plots.filter((c) =>
+          neighbors.includes(c),
+        ).length
         if (newTouches > 0) {
           touches += newTouches
           matchingRegions.push(region)
           regions.delete(region)
         }
       })
-      const newRegion = matchingRegions.reduce<Region>((acc, cur) => {
+      const newRegion = matchingRegions.reduce<Region>(
+        (acc, cur) => {
           acc.area += cur.area
           acc.perimeter += cur.perimeter
           acc.plots.push(...cur.plots)
           return acc
-      }, {
+        },
+        {
           symbol,
           area: 1,
           perimeter: 4 - 2 * touches,
           plots: [key],
-      })
+        },
+      )
       regions.add(newRegion)
     })
   })
 
-  return Array.from(regions).reduce((total, {
+  return Array.from(regions).reduce((total, { symbol, plots, area }) => {
-    symbol,
-    plots,
-    area,
-  }) => {
     let corners = 0
-    plots.forEach(plot => {
+    plots.forEach((plot) => {
-      const [r, c] = plot.split(',').map(Number)
+      const [r, c] = plot.split(",").map(Number)
-      const boundaries = getNeighbors(r, c).map(getKey).map((k, i) => plots.includes(k) ? '' : i).join('')
+      const orthogonalProbes = getNeighbors(r, c)
-      switch(boundaries) {
+        .map(getKey)
-        case '0123':
+        .map((k) => plots.includes(k))
-          corners += 4
+      const diagonalProbes = diagonals.map(([dr, dc]) =>
-          break
+        plots.includes(getKey([r + dr, c + dc])),
-        case '01':
+      )
-        case '12':
+      orthogonalProbes.forEach((presentThisDirection, thisDirection) => {
-        case '23':
+        const nextDirection = (thisDirection + 1) % 4
-        case '03':
+        const presentNextDirection = orthogonalProbes[nextDirection]
+        if (
+          presentThisDirection &&
+          presentNextDirection &&
+          !diagonalProbes[thisDirection]
+        ) {
+          corners += 1
+        }
+        if (!presentThisDirection && !presentNextDirection) {
           corners += 1
-          break
-        case '012':
-        case '123':
-        case '023':
-        case '013':
-          corners += 2
-          break
         }
       })
-    console.log(`Region of ${symbol} with ${corners} sides`)
+    })
     return total + corners * area
   }, 0)
 }
@@ -175,11 +192,11 @@ AAABBA
 ABBAAA
 ABBAAA
 AAAAAA`,
-        expected: 1206,
+        expected: 368,
-      }
+      },
     ],
     solution: part2,
   },
   trimTestInputs: true,
-  onlyTests: true,
+  onlyTests: false,
 })