Added 2017 day 21

Author: plasmapper

2017/21/code.mjs

@@ -0,0 +1,150 @@
+import { delay, Console } from "../../utility.mjs";
+
+export default class  {
+  /**
+   * @param {Console} solConsole Solution console.
+   * @param {HTMLElement} visContainer Visualization container.
+   */
+  constructor(solConsole, visContainer) {
+    this.isSolving = false;
+    this.isStopping = false;
+    this.solConsole = typeof solConsole !== "undefined" ? solConsole : new Console();
+    this.visContainer = visContainer;
+  }
+  
+  /**
+   * Parses the puzzle input.
+   * @param {string} input Puzzle input.
+   * @returns {EnhancementRule[]} Enhancement rules.
+   */
+  parse(input) {
+    let consoleLine = this.solConsole.addLine("Parsing...");
+
+    let enhancementRules = input.split(/\r?\n/).map((line, index) => {
+      let match = line.match(/^([\.\/#]+) => ([\.\/#]+)$/);
+      if (match == null)
+        throw new Error(`Invalid data in line ${index + 1}`);
+      
+      let from = match[1].split("/").map(e => e.split("").map(e => e == "#" ? 1 : 0));
+      let to = match[2].split("/").map(e => e.split("").map(e => e == "#" ? 1 : 0));
+
+      let flip = shape => shape.map((e1, y) => shape[0].map((e2, x) => shape[y][shape[0].length - 1 - x]));
+      let rotate = shape => shape[0].map((e1, x) => shape.map((e2, y) => shape[shape.length - 1 - y][x]));
+
+      if ((from.length == 2 && from.every(e => e.length == 2) && to.length == 3 && to.every(e => e.length == 3))
+        || (from.length == 3 && from.every(e => e.length == 3) && to.length == 4 && to.every(e => e.length == 4))) {
+        return new EnhancementRule([from, rotate(from), rotate(rotate(from)), rotate(rotate(rotate(from))),
+          flip(from), rotate(flip(from)), rotate(rotate(flip(from))), rotate(rotate(rotate(flip(from))))], to)
+      }
+      else
+        throw new Error(`Invalid data in line ${index + 1}`);
+    });
+
+    consoleLine.innerHTML += " done.";
+    return enhancementRules;
+  }
+
+  /**
+   * Finds the number of pixels that stay on after the specified number of iterations.
+   * @param {number} part Puzzle part.
+   * @param {string} input Puzzle input.
+   * @param {boolean} visualization Enable visualization.
+   * @returns {number} Number of pixels that stay on after the specified number of iterations.
+   */
+  async solve(part, input, visualization) {
+    try {
+      this.isSolving = true;
+
+      let enhancementRules = this.parse(input);
+      let image = [[0, 1, 0], [0, 0, 1], [1, 1, 1]];
+      let numberOfIterations = enhancementRules.length < 5 ? 2 : (part == 1 ? 5 : 18);
+
+      let visConsole = new Console();
+      if (visualization)
+        this.visContainer.append(visConsole.container);
+
+      for (let i = 0; i < numberOfIterations; i++) {
+        let imageSize = image.length;
+        let fromBlockSize = imageSize % 2 == 0 ? 2 : 3;
+        let toBlockSize = imageSize % 2 == 0 ? 3 : 4;
+        let newImageSize = imageSize % 2 == 0 ? imageSize / 2 * 3 : imageSize / 3 * 4;
+        let newImage = new Array(newImageSize).fill(null).map(e => e = new Array(newImageSize).fill(0));
+
+        for (let x = 0; x < imageSize / fromBlockSize; x++) {
+          for (let y = 0; y < imageSize / fromBlockSize; y++) {
+            for (let enhancementRuleIndex = 0, enhancementRuleApplied = false; enhancementRuleIndex < enhancementRules.length && !enhancementRuleApplied; enhancementRuleIndex++) {
+              let enhancementRule = enhancementRules[enhancementRuleIndex]
+              let to = enhancementRule.to;
+              if (to.length == toBlockSize) {
+                for (let fromIndex = 0; fromIndex < enhancementRule.from.length && !enhancementRuleApplied; fromIndex++) {
+                  let from = enhancementRule.from[fromIndex];
+                  if (from.length == fromBlockSize) {
+                    let match = true;
+                    for (let ix = 0; ix < fromBlockSize && match; ix++) {
+                      for (let iy = 0; iy < fromBlockSize && match; iy++) {
+                        if (from[iy][ix] != image[y * fromBlockSize + iy][x * fromBlockSize + ix])
+                          match = false;
+                      }
+                    }
+                    if (match) {
+                      for (let ix = 0; ix < toBlockSize; ix++) {
+                        for (let iy = 0; iy < toBlockSize; iy++)
+                          newImage[y * toBlockSize + iy][x * toBlockSize + ix] = to[iy][ix];
+                      }
+                      enhancementRuleApplied = true;
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+
+        image = newImage;
+
+        if (visualization) {
+          let numberOfOnPixels = image.reduce((acc, e) => acc + e.reduce((acc, e) => acc + e, 0), 0);
+          visConsole.addLine(`Iteration ${i + 1}: ${numberOfOnPixels} pixel${numberOfOnPixels == 1 ? "" : "s"} are on.`);
+        }
+      }
+
+      return image.reduce((acc, e) => acc + e.reduce((acc, e) => acc + e, 0), 0);
+    }
+    
+    finally {
+      this.isSolving = false;
+    }
+  }
+
+  /**
+   * Stops solving the puzzle.
+   */
+  async stopSolving() {
+    this.isStopping = true;
+    while (this.isSolving)
+      await(delay(10));
+    this.isStopping = false;
+  }
+}
+
+/**
+ * Puzzle particle class.
+ */
+class EnhancementRule {
+  /**
+   * @param {number[][][]} from From.
+   * @param {number[][]} to To.
+   */
+  constructor(from, to) {
+    /**
+     * From.
+     * @type {number[][]}
+     */
+    this.from = from;
+    /**
+     * To.
+     * @type {number[][]}
+     */
+    this.to = to;
+  }
+}

2017/21/testInput.txt

@@ -0,0 +1,2 @@
+../.# => ##./#../...
+.#./..#/### => #..#/..../..../#..#

tree.mjs

@@ -478,6 +478,10 @@ export const years = [
       {
         name: "Day 20: Particle Swarm", path: "./2017/20", taskUrl: "https://adventofcode.com/2017/day/20",
         answers: {part1: 3, part2: 1}
+      },
+      {
+        name: "Day 21: Fractal Art", path: "./2017/21", taskUrl: "https://adventofcode.com/2017/day/21",
+        answers: {part1: 12}
       }
     ]
   },