2020 day 17

2020/17/input.txt

@@ -0,0 +1,8 @@
+##.#...#
+#..##...
+....#..#
+....####
+#.#....#
+###.#.#.
+.#.#.#..
+.#.....#

2020/17/part1.js

@@ -0,0 +1,96 @@
+const fs = require('fs');
+const textIn = fs.readFileSync('./input.txt', 'utf-8');
+const iterAmt = 6;
+
+// make a list of points to add at first
+let startPoints = []
+// could do forEach() instead of map() but i already did it like this and it works
+startGrid = textIn.split('\n').map((line, y) => line.split('').map((point, x) => {
+  if (point=='#') {
+    startPoints.push([iterAmt+x,iterAmt+y,iterAmt])
+  }
+  return point=='#'
+}));
+// start with zero active cubes
+let runningTotal = 0;
+// create an empty pocket dimension
+let p = new Pocket()
+// add the points from the input
+startPoints.forEach(point => add(...point, p));
+
+for (let i = 0; i < iterAmt; i++) {
+  printLayer(p,iterAmt);
+
+  // create a deep copy of the current state
+  let next = p.map(layer => layer.map(row => row.map(cube => {return{active:cube.active,nearby:cube.nearby}})))
+
+  // for every single cube in the pocket dimension
+  p.forEach((layer, z) => layer.forEach((row, y) => row.forEach((cube, x) => {
+    // apply the game of life rules using p and store in next
+    if (cube.active && (cube.nearby < 2 || cube.nearby > 3)) {
+      remove(x,y,z,p,next)
+    } else if (!cube.active && (cube.nearby == 3)) {
+      add(x,y,z,p,next)
+    }
+  })))
+
+  p = next;
+}
+
+console.log(runningTotal);
+
+// -------------------------------
+
+function printLayer(pocket, layer) {
+  console.log( pocket[layer].reduce((a,b)=>a+b.reduce((c,d)=>c+(d.active?'\x1b[36m':'\x1b[0m')+(d.nearby.toString().length==1?'0':'')+d.nearby,'')+'\n',''))
+}
+
+// returns empty pocket dimension
+function Pocket () {
+  let pocket = [];
+  for (let z = 0; z < iterAmt*2+1; z++) {
+    let layer = []
+    for (let y = 0; y < iterAmt*2+startGrid.length; y++) {
+      let row = []
+      row = Array(iterAmt*2 + startGrid[0].length).fill(0).map(()=>{return{active:false,nearby:0}})
+      layer.push(row)
+    }
+    pocket.push(layer)
+  }
+  return pocket
+}
+
+
+function add (x,y,z,before,after=before) {
+  if (before[z][y][x].active) return before; // if it's already active, do nothing
+  runningTotal++;
+  after[z][y][x].active = true;
+  // for every cube near the one we just added
+  for (let layer = Math.max(z-1, 0); layer <= Math.min(z+1, before.length-1); layer++) {
+    for (let row = Math.max(y-1, 0); row <= Math.min(y+1, before[0].length-1); row++) {
+      for (let col = Math.max(x-1, 0); col <= Math.min(x+1, before[0][0].length-1); col++) {
+        // but not the one we just added
+        if (layer == z && row == y && col == x) continue;
+        // there now is one more nearby cube
+        after[layer][row][col].nearby++
+      }
+    }
+  }
+  return after;
+}
+
+// add and remove could be combined into one function but i did it like this and it works
+function remove (x,y,z,before,after=before) {
+  if (!before[z][y][x].active) return before;
+  runningTotal--;
+  after[z][y][x].active = false;
+  for (let layer = Math.max(z-1, 0); layer <= Math.min(z+1, before.length-1); layer++) {
+    for (let row = Math.max(y-1, 0); row <= Math.min(y+1, before[0].length-1); row++) {
+      for (let col = Math.max(x-1, 0); col <= Math.min(x+1, before[0][0].length-1); col++) {
+        if (layer == z && row == y && col == x) continue;
+        after[layer][row][col].nearby--
+      }
+    }
+  }
+  return after;
+}

2020/17/part2.js

@@ -0,0 +1,92 @@
+// luckily i built it so it was pretty easy to add a new dimension
+
+const fs = require('fs');
+const textIn = fs.readFileSync('./input.txt', 'utf-8');
+const iterAmt = 6;
+let startPoints = []
+startGrid = textIn.split('\n').map((line, y) => line.split('').map((point, x) => {
+  if (point=='#') {
+    startPoints.push([iterAmt+x,iterAmt+y,iterAmt,iterAmt])
+  }
+  return point=='#'
+}));
+
+let runningTotal = 0;
+let p = new Pocket()
+
+startPoints.forEach(point => add(...point, p));
+
+for (let i = 0; i < iterAmt; i++) {
+  printLayer(p,iterAmt,iterAmt);
+
+  let next = p.map(slice => slice.map(layer => layer.map(row => row.map(cube => {return{active:cube.active,nearby:cube.nearby}}))))
+
+  p.forEach((slice, w) => slice.forEach((layer, z) => layer.forEach((row, y) => row.forEach((cube, x) => {
+    if (cube.active && (cube.nearby < 2 || cube.nearby > 3)) {
+      remove(x,y,z,w,p,next)
+    } else if (!cube.active && (cube.nearby == 3)) {
+      add(x,y,z,w,p,next)
+    }
+  }))))
+
+  p = next;
+}
+console.log(runningTotal);
+
+function printLayer(pocket, slice, layer) {
+  console.log(pocket[slice][layer].reduce((a,b)=>a+b.reduce((c,d)=>c+(d.active?'\x1b[36m':'\x1b[0m')+(d.nearby.toString().length==1?'0':'')+d.nearby,'')+'\n',''))
+}
+
+function Pocket () {
+  let pocket = [];
+  for (let w = 0; w < iterAmt*2+1; w++) {
+    let slice = []
+    for (let z = 0; z < iterAmt*2+1; z++) {
+      let layer = []
+      for (let y = 0; y < iterAmt*2+startGrid.length; y++) {
+        let row = []
+        for (let x = 0; x < iterAmt*2+startGrid[0].length; x++) {
+          row.push({active:false,nearby:0})
+        }
+        layer.push(row)
+      }
+      slice.push(layer)
+    }
+    pocket.push(slice)
+  }
+  return pocket
+}
+
+function add (x,y,z,w,before,after=before) {
+  if (before[w][z][y][x].active) return before;
+  runningTotal++;
+  after[w][z][y][x].active = true;
+  for (let slice = Math.max(w-1, 0); slice <= Math.min(w+1, before.length-1); slice++) {
+    for (let layer = Math.max(z-1, 0); layer <= Math.min(z+1, before[0].length-1); layer++) {
+      for (let row = Math.max(y-1, 0); row <= Math.min(y+1, before[0][0].length-1); row++) {
+        for (let col = Math.max(x-1, 0); col <= Math.min(x+1, before[0][0][0].length-1); col++) {
+          if (slice == w && layer == z && row == y && col == x) continue;
+          after[slice][layer][row][col].nearby++
+        }
+      }
+    }
+  }
+  return after;
+}
+
+function remove (x,y,z,w,before,after=before) {
+  if (!before[w][z][y][x].active) return before;
+  runningTotal--;
+  after[w][z][y][x].active = false;
+  for (let slice = Math.max(w-1, 0); slice <= Math.min(w+1, before.length-1); slice++) {
+    for (let layer = Math.max(z-1, 0); layer <= Math.min(z+1, before[0].length-1); layer++) {
+      for (let row = Math.max(y-1, 0); row <= Math.min(y+1, before[0][0].length-1); row++) {
+        for (let col = Math.max(x-1, 0); col <= Math.min(x+1, before[0][0][0].length-1); col++) {
+          if (slice == w && layer == z && row == y && col == x) continue;
+          after[slice][layer][row][col].nearby--
+        }
+      }
+    }
+  }
+  return after;
+}

2020/17/test1.txt

@@ -0,0 +1,3 @@
+.#.
+..#
+###

README.md

@@ -57,3 +57,4 @@ if (advent) {
 14. [:star: :star:](https://adventofcode.com/2020/day/14 "see puzzle")
 15. [:star: :star:](https://adventofcode.com/2020/day/15 "see puzzle")
 16. [:star: :star:](https://adventofcode.com/2020/day/16 "see puzzle")
+17. [:star: :star:](https://adventofcode.com/2020/day/17 "see puzzle")