83 lines
1.7 KiB
JavaScript
83 lines
1.7 KiB
JavaScript
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const fs = require('fs/promises');
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const tailVisited = {'0-0': true};
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let hx = 0;
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let hy = 0;
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let tx = 0;
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let ty = 0;
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let lastHead = [0,0];
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const moveRope = (direction) => {
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console.log("Moving ", direction);
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lastHead = [hx, hy];
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switch (direction) {
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case "R":
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hx += 1;
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break;
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case "L":
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hx -= 1;
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break;
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case "U":
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hy -= 1;
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break;
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case "D":
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hy += 1;
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break;
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}
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if(Math.max(Math.abs(hx - tx), Math.abs(hy - ty)) > 1) {
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[tx, ty ] = lastHead;
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console.log("Moving Tail to: ", tx, ", ", ty);
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tailVisited[`${tx}-${ty}`] = true;
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}
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}
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const printGraph = () => {
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console.log("\n\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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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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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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moveRope(direction);
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//printGraph();
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}
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}
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console.log(Object.values(tailVisited).length);
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})();
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