136 lines
3.1 KiB
JavaScript
136 lines
3.1 KiB
JavaScript
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const fs = require('fs/promises');
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const tailVisited = {'0~0': true};
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const rope = [[0,0], [0,0], [0,0], [0,0], [0,0], [0,0], [0,0], [0,0], [0,0], [0,0]];
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const keypress = async () => {
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process.stdin.setRawMode(true)
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return new Promise(resolve => process.stdin.once('data', data => {
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const byteArray = [...data]
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if (byteArray.length > 0 && byteArray[0] === 3) {
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console.log('^C')
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process.exit(1)
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}
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process.stdin.setRawMode(false)
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resolve()
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}))
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}
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const moveRope = (direction) => {
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const lastSpot = [rope[0][0], rope[0][1]];
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switch (direction) {
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case "R":
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rope[0][0] += 1;
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break;
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case "L":
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rope[0][0] -= 1;
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break;
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case "U":
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rope[0][1] -= 1;
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break;
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case "D":
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rope[0][1] += 1;
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break;
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}
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for(let i = 1; i < rope.length; ++i) {
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rope[i] = moveSeg(rope[i], i)
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}
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}
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const moveSeg = ([x, y], i) => {
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if(i === rope.length) return;
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const seg = rope[i - 1];
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//console.log("uhh: ", rope, " ", i, " ", seg);
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const [lx, ly] = seg;
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V= rope[i - 1];
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if(lx === x) {
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if(ly === y + 2) {
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return [x, y + 1];
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}
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if(ly === y - 2) {
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return[x, y - 1];
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}
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}
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if(ly === y) {
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if(lx === x + 2) {
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return [x + 1, y];
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}
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if(lx === x - 2) {
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return rope[i] = [x - 1, y];
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}
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}
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if(Math.max(Math.abs(x - lx), Math.abs(y - ly)) > 1) {
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const xDiff = lx - x;
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const yDiff = ly - y;
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if(xDiff === 0 || yDiff === 0) {
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console.log([x, y, lx, ly])
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console.log("ROPE: ", rope);
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}
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return [x + xDiff/Math.abs(xDiff), y + yDiff/Math.abs(yDiff)];
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}
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return [x, y];
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}
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const printGraph = () => {
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console.log("\n");
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console.log(rope);
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console.log("\n");
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for(let y = -15; y <= 15; y++) {
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const row = ["·", "·", "·", "·", "·",
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"·", "·", "·", "·", "·",
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"·", "·", "·", "·", "·",
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"·", "·", "·", "·", "·",
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"·", "·", "·", "·", "·",
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"·", "·", "·", "·", "·", "·"].map((spot, i) => {
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const x = i - 15;
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const [hx, hy] = rope[0];
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const [tx, ty] = rope[9];
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let ch = "·";
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if(!(y % 5) && !(x % 5)) {
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ch = "▪";
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}
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if(y === 0 && x === 0) {
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ch = "0";
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}
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if(y === ty && x === tx) {
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ch = "T";
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}
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rope.slice(0, -1).reverse().forEach(([a, b], j) => {
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if(a === x && b === y) {
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ch = j+1;
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}
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});
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if(y === hy && x === hx) {
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ch = "H";
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}
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return ch;
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});
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console.log(row.join(""));
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}
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console.log("\n\n");
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};
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(async () => {
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const input = await fs.readFile("./input.txt", 'utf8');
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const lines = input.split("\n").map(t => t.split(" "));
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//printGraph();
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for (const [direction, times] of lines) {
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for(let i = 0; i < times; ++i) {
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//await keypress();
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console.log("Moving ", direction);
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moveRope(direction);
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//printGraph();
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tailVisited[`${rope[9][0]}~${rope[9][1]}`] = true;
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}
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}
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console.log(tailVisited);
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console.log(Object.values(tailVisited).length);
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})();
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