.

2021/10.js

@@ -0,0 +1,30 @@
+const opens = ["(", "[", "{", "<"]
+const closes = [")", "]", "}", ">"]
+const scores1 = { ")": 3, "]": 57, "}": 1197, ">": 25137 }
+const scores2 = { ")": 1, "]": 2, "}": 3, ">": 4 }
+
+function parse(str) {
+    let stack = []
+
+    for (let i = 0; i < str.length; i++) {
+        let char = str[i]
+
+        if (opens.includes(char)) {
+            stack.push(closes[opens.indexOf(char)])
+        } else if (char != stack.pop()) {
+            return scores1[char]
+        }
+    }
+
+    return stack.reverse()
+}
+
+function day10(input, part2) {
+    let results = input.split("\n").map(parse)
+
+    if (!part2) {
+        return results.filter((e) => !Array.isArray(e)).sum()
+    } else {
+        return results.filter((e) => Array.isArray(e)).map((e) => e.reduce((a, b) => a * 5 + scores2[b], 0)).medianNumeric()
+    }
+}

2021/9.js

@@ -0,0 +1,15 @@
+function day9(input, part2) {
+    let grid = Grid.fromStr(input).num()
+
+    let lows = grid.findAllIndices((e, pt, g) => g.getAdjNeighbors(pt).every((nb) => e < g.get(nb)))
+
+    if (!part2) {
+        return lows.map((e) => grid.get(e) + 1).sum()
+    }
+
+    let sizes = lows.map((low) => grid.bfs(low, (e, pt, g) => {
+        return e == 9 || g.get(pt.path.last) < e ? Grid.BFS_STOP : Grid.BFS_CONTINUE
+    }).filter((e) => e.result == Grid.BFS_CONTINUE).length).sort((a, b) => b - a)
+
+    return sizes[0] * sizes[1] * sizes[2]
+}

grid.js

@@ -97,7 +97,7 @@ Grid = class Grid {
 	}
 
 	findAllIndices(func) {
-		let points = []
+		let points = [].pt
 		this.forEach((e, pt, grid) => func(e, pt, grid) ? points.push(pt) : 0)
 		return points
 	}
@@ -130,7 +130,7 @@ Grid = class Grid {
 	static BFS_STOP = 1
 	static BFS_END = 2
 
-	bfs(pt, func, neighbors = "getAdjNeighborsThat", getlimit = 1000) {
+	bfs(pt, func, neighbors = "getAdjNeighborsThat", limit = 1000) {
 		let visited = [].pt
 		let toVisit = [pt].pt
 		let count = 0
@@ -144,14 +144,16 @@ Grid = class Grid {
 			toVisit.sort()
 
 			for (let i = 0; i < toVisit.length; i++) {
-				let result = func(this.get(toVisit[i]), toVisit[i], this, visited);
+				let v = toVisit[i]
 
-				if (result == Grid.BFS_CONTINUE) {
+				v.result = func(this.get(v), v, this, visited)
-					newToVisit.pushUniq(...this[neighbors](toVisit[i], (pt) => !pt.isIn(visited)).map((pt) => (pt.path = [...toVisit[i].path, pt], pt)))
+
+				if (v.result == Grid.BFS_CONTINUE) {
+					newToVisit.pushUniq(...this[neighbors](v, (pt) => !pt.isIn(visited)).map((pt) => (pt.path = [...v.path, pt], pt)))
 				}
 
-				if (result == Grid.BFS_END) {
+				if (v.result == Grid.BFS_END) {
-					end = toVisit[i]
+					end = v
 					break out
 				}
 			}

out.js

@@ -338,7 +338,7 @@ Grid = class Grid {
 	}
 
 	findAllIndices(func) {
-		let points = []
+		let points = [].pt
 		this.forEach((e, pt, grid) => func(e, pt, grid) ? points.push(pt) : 0)
 		return points
 	}
@@ -371,7 +371,7 @@ Grid = class Grid {
 	static BFS_STOP = 1
 	static BFS_END = 2
 
-	bfs(pt, func, neighbors = "getAdjNeighborsThat", getlimit = 1000) {
+	bfs(pt, func, neighbors = "getAdjNeighborsThat", limit = 1000) {
 		let visited = [].pt
 		let toVisit = [pt].pt
 		let count = 0
@@ -385,14 +385,16 @@ Grid = class Grid {
 			toVisit.sort()
 
 			for (let i = 0; i < toVisit.length; i++) {
-				let result = func(this.get(toVisit[i]), toVisit[i], this, visited);
+				let v = toVisit[i]
 
-				if (result == Grid.BFS_CONTINUE) {
+				v.result = func(this.get(v), v, this, visited)
-					newToVisit.pushUniq(...this[neighbors](toVisit[i], (pt) => !pt.isIn(visited)).map((pt) => (pt.path = [...toVisit[i].path, pt], pt)))
+
+				if (v.result == Grid.BFS_CONTINUE) {
+					newToVisit.pushUniq(...this[neighbors](v, (pt) => !pt.isIn(visited)).map((pt) => (pt.path = [...v.path, pt], pt)))
 				}
 
-				if (result == Grid.BFS_END) {
+				if (v.result == Grid.BFS_END) {
-					end = toVisit[i]
+					end = v
 					break out
 				}
 			}
@@ -661,6 +663,14 @@ PtArray = PointArray = class PointArray extends Array {
 
 		return arr
 	}
+
+	static revert(arr) {
+		if (arr.__proto__ != Array.prototype) {
+			arr.__proto__ = Array.prototype
+		}
+
+		return arr
+	}
 }
 
 let warned = false
@@ -891,6 +901,17 @@ load = function load() {
 			},
 			configurable: true
 		},
+		medianNumeric: {
+			value: function() {
+				let sorted = this.copy().sort((a, b) => a - b)
+
+				if (sorted.length % 2) {
+					return sorted[(sorted.length - 1) / 2]
+				} else {
+					return (sorted[sorted.length / 2 - 1] + sorted[sorted.length / 2]) / 2
+				}
+			},
+		},
 		freqs: {
 			value: function() {
 				return this.uniq().map((e) => [e, this.count(e)])
@@ -912,6 +933,18 @@ load = function load() {
 	})
 
 	Object.defineProperties(PointArray.prototype, {
+		arr: {
+			get: function() {
+				return PointArray.revert(this)
+			},
+			configurable: true
+		},
+		map: {
+			value: function(...args) {
+				return this.arr.map(...args)
+			},
+			configurable: true
+		},
 		splitOnElement: {
 			value: function(sep) {
 				let arr = [[]]

proto.js

@@ -6,6 +6,14 @@ PtArray = PointArray = class PointArray extends Array {
 
 		return arr
 	}
+
+	static revert(arr) {
+		if (arr.__proto__ != Array.prototype) {
+			arr.__proto__ = Array.prototype
+		}
+
+		return arr
+	}
 }
 
 let warned = false
@@ -236,6 +244,17 @@ load = function load() {
 			},
 			configurable: true
 		},
+		medianNumeric: {
+			value: function() {
+				let sorted = this.copy().sort((a, b) => a - b)
+
+				if (sorted.length % 2) {
+					return sorted[(sorted.length - 1) / 2]
+				} else {
+					return (sorted[sorted.length / 2 - 1] + sorted[sorted.length / 2]) / 2
+				}
+			},
+		},
 		freqs: {
 			value: function() {
 				return this.uniq().map((e) => [e, this.count(e)])
@@ -257,6 +276,18 @@ load = function load() {
 	})
 
 	Object.defineProperties(PointArray.prototype, {
+		arr: {
+			get: function() {
+				return PointArray.revert(this)
+			},
+			configurable: true
+		},
+		map: {
+			value: function(...args) {
+				return this.arr.map(...args)
+			},
+			configurable: true
+		},
 		splitOnElement: {
 			value: function(sep) {
 				let arr = [[]]