.

2021/11.js

@@ -0,0 +1,34 @@
+function day11(input, part2) {
+    let grid = Grid.fromStr(input).mapMut((e) => ({ energy: +e, flashed: false }))
+
+    let steps = 0
+    let flashes = 0
+    let totalFlashes = 0
+
+    while (part2 ? flashes != grid.width * grid.height : steps < 100) {
+        flashes = 0
+
+        grid.forEach(function flash(e, pt, g) {
+            e.energy++
+
+            if (!e.flashed && e.energy > 9) {
+                e.flashed = true
+                flashes++
+
+                g.getAllNeighborsThat(pt, (e) => !e.flashed).forEach((pt) => flash(g.get(pt), pt, g))
+            }
+        })
+
+        grid.forEach((e) => {
+            if (e.flashed) {
+                e.energy = 0
+                e.flashed = false
+            }
+        })
+
+        steps++
+        totalFlashes += flashes
+    }
+
+    return part2 ? steps : totalFlashes
+}

2021/12.js

@@ -0,0 +1,42 @@
+// TODO: not very efficient because i was lazy
+
+function day12(input, part2) {
+    let cxns = input.split("\n").map((line) => line.split("-"))
+    let dict = {}
+
+    for (let cxn of cxns) {
+        dict[cxn[0]] = [...(dict[cxn[0]] || []), cxn[1]]
+        dict[cxn[1]] = [...(dict[cxn[1]] || []), cxn[0]]
+    }
+
+    let count = 0
+    let paths = [["start"]]
+
+    while (paths.length) {
+        let newPaths = []
+
+        for (let path of paths) {
+            for (let next of dict[path.last]) {
+                if (next == "start") {
+                    continue
+                }
+
+                let newPath = [...path, next]
+
+                if (newPath.count((e, i, a) => e == e.toLowerCase() && a.indexOf(e) != i) > part2) {
+                    continue
+                }
+
+                if (next == "end") {
+                    count++
+                } else {
+                    newPaths.push(newPath)
+                }
+            }
+        }
+
+        paths = newPaths
+    }
+
+    return count
+}

2021/13.js

@@ -0,0 +1,27 @@
+function day13(input, part2) {
+    input = input.split("\n").splitOnElement("")
+
+    let points = input[0].map((e) => new Point(...e.split(",").num())).pt
+    let instructions = input[1].map((e) => e.split(" ").last.split("=")).map((e) => [e[0], +e[1]])
+
+    for (let instruction of instructions) {
+        let pos = instruction[1]
+        let newPoints = [].pt
+
+        for (let point of points) {
+            if (instruction[0] == "x") {
+                newPoints.push(point.x < pos ? point : new Point(2 * pos - point.x, point.y))
+            } else {
+                newPoints.push(point.y < pos ? point : new Point(point.x, 2 * pos - point.y))
+            }
+        }
+
+        points = newPoints.uniq()
+
+        if (!part2) {
+            return points.length
+        }
+    }
+
+    return new Grid(points.max((e) => e.x).x + 1, points.max((e) => e.y).y + 1).mapMut((_, pt) => pt.isIn(points) ? "#" : " ").toString("")
+}

grid.js

@@ -80,6 +80,8 @@ Grid = class Grid {
 	}
 
 	findIndex(func) {
+		func = typeof func == "function" ? func : (e) => e == func
+
 		for (let y = 0; y < this.height; y++) {
 			for (let x = 0; x < this.width; x++) {
 				let pt = new Point(x, y)
@@ -97,8 +99,11 @@ Grid = class Grid {
 	}
 
 	findAllIndices(func) {
+		func = typeof func == "function" ? func : (e) => e == func
+
 		let points = [].pt
 		this.forEach((e, pt, grid) => func(e, pt, grid) ? points.push(pt) : 0)
+
 		return points
 	}
 
@@ -106,6 +111,10 @@ Grid = class Grid {
 		return this.findAllIndices(func).map((pt) => this.get(pt))
 	}
 
+	count(func) {
+		return this.findAllIndices(func).length
+	}
+
 	indexOf(val) {
 		return this.findIndex((e) => e == val)
 	}

out.js

@@ -199,12 +199,12 @@ Pt = Point = class Point {
 	dl() { return this.downleft() }
 	dr() { return this.downright() }
 
-	getUnfilteredAdjNeighbors() { return [this.u(), this.l(), this.r(), this.d()] }
+	getUnfilteredAdjNeighbors() { return new PointArray(this.u(), this.l(), this.r(), this.d()) }
-	getUnfilteredDiagNeighbors() { return [this.ul(), this.ur(), this.dl(), this.dr()] }
+	getUnfilteredDiagNeighbors() { return new PointArray(this.ul(), this.ur(), this.dl(), this.dr()) }
-	getUnfilteredAllNeighbors() { return [this.ul(), this.u(), this.ur(), this.l(), this.r(), this.dl(), this.d(), this.dr()] }
+	getUnfilteredAllNeighbors() { return new PointArray(this.ul(), this.u(), this.ur(), this.l(), this.r(), this.dl(), this.d(), this.dr()) }
-	getUnfilteredAdjNeighborsIncSelf() { return [this.u(), this.l(), this, this.r(), this.d()] }
+	getUnfilteredAdjNeighborsIncSelf() { return new PointArray(this.u(), this.l(), this, this.r(), this.d()) }
-	getUnfilteredDiagNeighborsIncSelf() { return [this.ul(), this.ur(), this, this.dl(), this.dr()] }
+	getUnfilteredDiagNeighborsIncSelf() { return new PointArray(this.ul(), this.ur(), this, this.dl(), this.dr()) }
-	getUnfilteredAllNeighborsIncSelf() { return [this.ul(), this.u(), this.ur(), this.l(), this, this.r(), this.dl(), this.d(), this.dr()] }
+	getUnfilteredAllNeighborsIncSelf() { return new PointArray(this.ul(), this.u(), this.ur(), this.l(), this, this.r(), this.dl(), this.d(), this.dr()) }
 
 	add(pt) { return new Point(this.x + pt.x, this.y + pt.y) }
 	addMut(pt) {
@@ -321,6 +321,8 @@ Grid = class Grid {
 	}
 
 	findIndex(func) {
+		func = typeof func == "function" ? func : (e) => e == func
+
 		for (let y = 0; y < this.height; y++) {
 			for (let x = 0; x < this.width; x++) {
 				let pt = new Point(x, y)
@@ -338,8 +340,11 @@ Grid = class Grid {
 	}
 
 	findAllIndices(func) {
+		func = typeof func == "function" ? func : (e) => e == func
+
 		let points = [].pt
 		this.forEach((e, pt, grid) => func(e, pt, grid) ? points.push(pt) : 0)
+
 		return points
 	}
 
@@ -347,6 +352,10 @@ Grid = class Grid {
 		return this.findAllIndices(func).map((pt) => this.get(pt))
 	}
 
+	count(func) {
+		return this.findAllIndices(func).length
+	}
+
 	indexOf(val) {
 		return this.findIndex((e) => e == val)
 	}

pt.js

@@ -27,12 +27,12 @@ Pt = Point = class Point {
 	dl() { return this.downleft() }
 	dr() { return this.downright() }
 
-	getUnfilteredAdjNeighbors() { return [this.u(), this.l(), this.r(), this.d()] }
+	getUnfilteredAdjNeighbors() { return new PointArray(this.u(), this.l(), this.r(), this.d()) }
-	getUnfilteredDiagNeighbors() { return [this.ul(), this.ur(), this.dl(), this.dr()] }
+	getUnfilteredDiagNeighbors() { return new PointArray(this.ul(), this.ur(), this.dl(), this.dr()) }
-	getUnfilteredAllNeighbors() { return [this.ul(), this.u(), this.ur(), this.l(), this.r(), this.dl(), this.d(), this.dr()] }
+	getUnfilteredAllNeighbors() { return new PointArray(this.ul(), this.u(), this.ur(), this.l(), this.r(), this.dl(), this.d(), this.dr()) }
-	getUnfilteredAdjNeighborsIncSelf() { return [this.u(), this.l(), this, this.r(), this.d()] }
+	getUnfilteredAdjNeighborsIncSelf() { return new PointArray(this.u(), this.l(), this, this.r(), this.d()) }
-	getUnfilteredDiagNeighborsIncSelf() { return [this.ul(), this.ur(), this, this.dl(), this.dr()] }
+	getUnfilteredDiagNeighborsIncSelf() { return new PointArray(this.ul(), this.ur(), this, this.dl(), this.dr()) }
-	getUnfilteredAllNeighborsIncSelf() { return [this.ul(), this.u(), this.ur(), this.l(), this, this.r(), this.dl(), this.d(), this.dr()] }
+	getUnfilteredAllNeighborsIncSelf() { return new PointArray(this.ul(), this.u(), this.ur(), this.l(), this, this.r(), this.dl(), this.d(), this.dr()) }
 
 	add(pt) { return new Point(this.x + pt.x, this.y + pt.y) }
 	addMut(pt) {