37 lines
821 B
JavaScript
37 lines
821 B
JavaScript
import fs from "fs-extra";
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import fp from "lodash/fp.js";
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import _ from "lodash";
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import * as p1 from "./part1.mjs";
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function getBasinSize([x, y], grid, seen) {
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if (seen[x][y]) return 0;
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seen[x][y] = true;
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if (grid[x][y] == 9) return 0;
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const neighbours = p1.genNeighbours(grid.length, grid[0].length);
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return _.sum([
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1,
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...neighbours(x, y).map((n) => getBasinSize(n, grid, seen)),
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]);
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}
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export function solution(grid) {
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const seen = grid.map(() => []);
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let basinSizes = [];
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for (const x of _.range(grid.length)) {
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for (const y of _.range(grid[x].length)) {
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basinSizes.push(getBasinSize([x, y], grid, seen));
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}
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}
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return basinSizes
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.sort((a, b) => (a > b ? 1 : -1))
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.splice(-3)
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.reduce(_.multiply);
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}
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