day 15

.aocrunner.json

@@ -223,16 +223,16 @@
     },
     {
       "part1": {
-        "solved": false,
+        "solved": true,
-        "result": null,
+        "result": "1446158",
         "attempts": [],
-        "time": null
+        "time": 4.47472
       },
       "part2": {
-        "solved": false,
+        "solved": true,
-        "result": null,
+        "result": "1446175",
         "attempts": [],
-        "time": null
+        "time": 7.353299
       }
     },
     {

README.md

@@ -25,7 +25,7 @@
 [![Day](https://badgen.net/badge/12/%E2%98%85%E2%98%85/green)](src/day12)
 [![Day](https://badgen.net/badge/13/%E2%98%85%E2%98%85/green)](src/day13)
 [![Day](https://badgen.net/badge/14/%E2%98%85%E2%98%86/yellow)](src/day14)
-![Day](https://badgen.net/badge/15/%E2%98%86%E2%98%86/gray)
+[![Day](https://badgen.net/badge/15/%E2%98%85%E2%98%85/green)](src/day15)
 ![Day](https://badgen.net/badge/16/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/17/%E2%98%86%E2%98%86/gray)
 ![Day](https://badgen.net/badge/18/%E2%98%86%E2%98%86/gray)
@@ -160,16 +160,16 @@ Both parts: 1.913ms
 
 ```
 Day 14
-Time part 1: 1.507ms
+Time part 1: 1.492ms
 Time part 2: -
-Both parts: 1.507ms
+Both parts: 1.492ms
 ```
 
 ```
 Day 15
 Time part 1: -
-Time part 2: -
+Time part 2: 7.672ms
-Both parts: -
+Both parts: 7.672ms
 ```
 
 ```
@@ -243,8 +243,8 @@ Both parts: -
 ```
 
 ```
-Total stars: 27/50
+Total stars: 29/50
-Total time: 38905.685ms
+Total time: 38913.342ms
 ```
 
 <!--/RESULTS-->

src/day15/README.md

@@ -0,0 +1,9 @@
+# 🎄 Advent of Code 2024 - day 15 🎄
+
+## Info
+
+Task description: [link](https://adventofcode.com/2024/day/15)
+
+## Notes
+
+...

src/day15/index.ts

@@ -0,0 +1,224 @@
+import run from "aocrunner"
+
+type Coord = [number, number]
+
+const getKey = (r: number, c: number) => {
+  return r * 100 + c
+}
+type Key = ReturnType<typeof getKey>
+
+const deltas: Record<string, Coord> = {
+  "^": [-1, 0],
+  ">": [0, 1],
+  v: [1, 0],
+  "<": [0, -1],
+}
+
+const part1 = (rawInput: string) => {
+  // Parsing
+  const [rawMap, rawMovements] = rawInput.split("\n\n")
+  const map = rawMap.split("\n").map(line => line.split(''))
+  let start: Coord
+  let boxes = new Set<Key>()
+  const walls = new Set<Key>()
+  map.forEach((line, r) => {
+    line.forEach((cell, c) => {
+      const key = getKey(r, c)
+      if (cell === "O") {
+        boxes.add(key)
+      }
+      if (cell === "@") {
+        start = [r, c]
+      }
+      if (cell === "#") {
+        walls.add(key)
+      }
+    })
+  })
+  const movements = rawMovements.replaceAll("\n", "").split("")
+
+  // Solving
+  let [rPos, cPos] = start
+  movements.forEach((move) => {
+    const [dr, dc] = deltas[move]
+    for (let i = 1; ; i++) {
+      const key = getKey(rPos + dr * i, cPos + dc * i)
+      if (walls.has(key)) return // no space before hitting wall, do nothing
+      if (boxes.has(key)) continue // only boxes so far
+      // an open space!
+      if (i > 1) {
+        boxes.delete(getKey(rPos+dr, cPos+dc))
+        boxes.add(key)
+        break
+      }
+      break
+    }
+    rPos += dr
+    cPos += dc
+
+    // Uncomment to show moves
+
+    // console.log(move)
+    // map.forEach((row,r) => {
+    //   const line = row.map((_, c) => {
+    //     const key = getKey(r,c)
+    //     if (boxes.has(key)) return "O"
+    //     if (walls.has(key)) return "#"
+    //     if (rPos === r && cPos === c) return "@"
+    //     return " "
+    //   }).join('')
+    //   console.log(line)
+    // })
+    // console.log('')
+  })
+  return Array.from(boxes.values()).reduce((total, b) => total + b, 0)
+}
+
+const part2 = (rawInput: string) => {
+  // Parsing
+  const [rawMap, rawMovements] = rawInput.split("\n\n")
+  const map = rawMap.split("\n").map(line => line.split(''))
+  let start: Coord
+  let boxes = new Set<Key>()
+  const walls = new Set<Key>()
+  map.forEach((line, r) => {
+    line.forEach((cell, c) => {
+      const key = getKey(r, c * 2)
+      if (cell === "O") {
+        boxes.add(key)
+      }
+      if (cell === "@") {
+        start = [r, c * 2]
+      }
+      if (cell === "#") {
+        walls.add(key)
+        walls.add(getKey(r, 2 * c + 1))
+      }
+    })
+  })
+  const movements = rawMovements.replaceAll("\n", "").split("")
+
+  // Solving
+  let [rPos, cPos] = start
+ 
+  movements.forEach((instruction) => {
+    const [dr, dc] = deltas[instruction]
+    if (dr === 0) { // horizontal movement
+      for (let i = 1; ; i++) {
+        const key = getKey(rPos, cPos + dc * i)
+        if (walls.has(key)) return // no space before hitting wall, do nothing
+        if (dc > 0 && boxes.has(key)) {
+          i++
+          continue
+        }
+        if (dc < 0 && boxes.has(getKey(rPos, cPos - i - 1))) {
+          i++
+          continue
+        }
+        // an open space!
+        if (i > 1) {
+          for (let j = 1; j < i; j += 2) {
+            const offset = dc < 0 ? 1 : 0
+            boxes.delete(getKey(rPos, cPos+(j+offset)*dc))
+            boxes.add(getKey(rPos, cPos+(j+offset+1)*dc))
+          }
+          break
+        }
+        break
+      }
+    }
+    // vertical movement, dc is 0
+
+    const toDelete: Key[] = []
+    const toAdd: Key[] = []
+    // solve this with recursion!
+    const move = (r: number, c: number, dr: number): boolean => {
+      const keyAhead = getKey(r + dr, c)
+      if (walls.has(keyAhead)) return false
+      if (boxes.has(keyAhead)) {
+        if (move(r + dr, c, dr) && move(r + dr, c + 1, dr)) {
+          toDelete.push(keyAhead)
+          toAdd.push(getKey(r+2*dr, c))
+          return true
+        }
+        return false
+      }
+      const keyLeftAhead = getKey(r + dr, c-1)
+      if (boxes.has(keyLeftAhead)) {
+        if (move(r + dr, c - 1, dr) && move(r + dr, c, dr)) {
+          toDelete.push(keyLeftAhead)
+          toAdd.push(getKey(r + 2*dr, c - 1))
+          return true
+        }
+        return false
+      }
+      return true
+    }
+    if (move(rPos, cPos, dr)) {
+      toDelete.forEach(k => boxes.delete(k))
+      toAdd.forEach(k => boxes.add(k))
+    } else {
+      return
+    }
+
+    rPos += dr
+    cPos += dc
+
+    // Uncomment to show moves
+
+    // console.log(instruction)
+    // map.forEach((row,r) => {
+    //   const line = new Array(row.length * 2).fill(0).map((_, c) => {
+    //     const key = getKey(r,c)
+    //     if (rPos === r && cPos === c) return "@"
+    //     if (boxes.has(key)) return "["
+    //     if (boxes.has(getKey(r, c-1))) return "]"
+    //     if (walls.has(key)) return "#"
+    //     return "."
+    //   }).join('')
+    //   console.log(line)
+    // })
+    // console.log('')
+  })
+  return Array.from(boxes.values()).reduce((total, b) => total + b, 0)
+}
+
+run({
+  part1: {
+    tests: [
+      {
+        input: `########
+#..O.O.#
+##@.O..#
+#...O..#
+#.#.O..#
+#...O..#
+#......#
+########
+
+<^^>>>vv<v>>v<<`,
+        expected: 2028,
+      },
+    ],
+    solution: part1,
+  },
+  part2: {
+    tests: [
+      {
+        input: `#######
+#...#.#
+#.....#
+#..OO@#
+#..O..#
+#.....#
+#######
+
+<vv<<^^<<^^`,
+        expected: 618,
+      },
+    ],
+    solution: part2,
+  },
+  trimTestInputs: true,
+  onlyTests: false,
+})