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mastermatt/day3.js

Last active December 3, 2019 16:31
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  1. mastermatt revised this gist Dec 3, 2019. 1 changed file with 6 additions and 6 deletions.
    12 changes: 6 additions & 6 deletions day3.js
    View file
    Original file line number Diff line number Diff line change
    @@ -73,15 +73,15 @@ const dirsToWire = dirs => {
    });
    };

    const aWires = dirsToWire(aWireDirs.split(","));
    const bWires = dirsToWire(bWireDirs.split(","));
    const aWire = dirsToWire(aWireDirs.split(","));
    const bWire = dirsToWire(bWireDirs.split(","));
    const distancesToOrigin = [];
    const combinedStepsToIntersections = [];

    let wireBDist = 0;
    for (const bLine of bWires) {
    for (const bLine of bWire) {
    let wireADist = 0;
    for (const aLine of aWires) {
    for (const aLine of aWire) {
    const intersection = aLine.intersection(bLine);
    if (intersection) {
    distancesToOrigin.push(Line.length(origin, intersection));
    @@ -98,5 +98,5 @@ for (const bLine of bWires) {
    wireBDist += bLine.length;
    }

    console.log("##### part one", Math.min(...distancesToOrigin)); // 1195
    console.log("##### part two", Math.min(...combinedStepsToIntersections)); // 91518
    console.log("##### part one", Math.min(...distancesToOrigin));
    console.log("##### part two", Math.min(...combinedStepsToIntersections));
  2. mastermatt created this gist Dec 3, 2019.
    102 changes: 102 additions & 0 deletions day3.js
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,102 @@
    const fs = require("fs");
    const path = require("path");

    const [aWireDirs, bWireDirs] = fs
    .readFileSync(path.resolve(__dirname, "./day3_input.txt"))
    .toString()
    .split("\n");

    class Point {
    constructor(x, y) {
    this.x = x;
    this.y = y;
    }

    add(vector) {
    return new Point(this.x + vector.x, this.y + vector.y);
    }
    }

    const origin = new Point(0, 0);

    class Line {
    constructor(a, b) {
    this.a = a;
    this.b = b;
    }

    get isHorizontal() {
    return this.a.y === this.b.y;
    }

    get length() {
    return Line.length(this.a, this.b);
    }

    static length(a, b) {
    return Math.abs(a.x - b.x) + Math.abs(a.y - b.y);
    }

    intersection(other) {
    if (this.isHorizontal === other.isHorizontal) {
    return null;
    }

    const [h, v] = this.isHorizontal ? [this, other] : [other, this];
    const between = (a, b, c) => (b < c ? a > b && a < c : a > c && a < b);

    if (between(v.a.x, h.a.x, h.b.x) && between(h.a.y, v.a.y, v.b.y)) {
    return new Point(v.a.x, h.a.y);
    }
    return null;
    }
    }

    const dirToVector = input => {
    const [dir, ...rest] = input;
    let dis = Number(rest.join(""));
    if (dir === "D" || dir === "L") {
    dis *= -1;
    }

    return dir === "R" || dir === "L" ? new Point(dis, 0) : new Point(0, dis);
    };

    const dirsToWire = dirs => {
    let start = origin;

    return dirs.map(dir => {
    const end = start.add(dirToVector(dir));
    const line = new Line(start, end);
    start = end;
    return line;
    });
    };

    const aWires = dirsToWire(aWireDirs.split(","));
    const bWires = dirsToWire(bWireDirs.split(","));
    const distancesToOrigin = [];
    const combinedStepsToIntersections = [];

    let wireBDist = 0;
    for (const bLine of bWires) {
    let wireADist = 0;
    for (const aLine of aWires) {
    const intersection = aLine.intersection(bLine);
    if (intersection) {
    distancesToOrigin.push(Line.length(origin, intersection));

    combinedStepsToIntersections.push(
    wireADist +
    wireBDist +
    Line.length(aLine.a, intersection) +
    Line.length(bLine.a, intersection)
    );
    }
    wireADist += aLine.length;
    }
    wireBDist += bLine.length;
    }

    console.log("##### part one", Math.min(...distancesToOrigin)); // 1195
    console.log("##### part two", Math.min(...combinedStepsToIntersections)); // 91518