82 lines
1.9 KiB
TypeScript
82 lines
1.9 KiB
TypeScript
import { multBy } from '../../utils/array.ts';
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import { randomInt } from '../../utils/random.ts';
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function trySolve(
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nodes: { node: string; weight: number }[],
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edges: [string, string][]
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) {
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while (nodes.length > 2) {
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const randEdgeIdx = randomInt(0, edges.length);
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const [u, v] = edges.splice(randEdgeIdx, 1)[0];
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const vertexU = nodes.find((n) => n.node === u)!;
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const vertexVIdx = nodes.findIndex((n) => n.node === v);
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const vertexV = nodes.splice(vertexVIdx, 1)[0];
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const oldNodes = [u, v];
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const mergedName = `(${u}:${v})`;
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const newEdges = edges
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.map(
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(e) =>
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[
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oldNodes.includes(e[0]) ? mergedName : e[0],
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oldNodes.includes(e[1]) ? mergedName : e[1]
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] as [string, string]
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)
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.filter((e) => e[0] !== e[1]);
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edges.length = 0;
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edges.push(...newEdges);
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vertexU.node = mergedName;
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vertexU.weight += vertexV.weight;
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}
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const edgeLength = edges.length;
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const mult = multBy(nodes, (n) => n.weight);
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return { edgeLength, mult };
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}
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export function solveFirst(input: string): number {
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const regex = /^(\w*): (.*)$/gm;
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const match = input.matchAll(regex);
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const { edges, nodesSet } = Array.from(
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match,
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(m) => [m[1], m[2].split(' ')] as [string, string[]]
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).reduce(
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({ edges, nodesSet }, line) => {
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nodesSet.add(line[0]);
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line[1].forEach((n) => {
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nodesSet.add(n);
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edges.push([line[0], n]);
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});
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return { edges, nodesSet };
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},
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{
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edges: [] as [string, string][],
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nodesSet: new Set<string>()
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}
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);
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let edgeLength, mult;
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let i = 0;
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do {
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i++;
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const result = trySolve(
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Array.from(nodesSet, (n) => ({ node: n, weight: 1 })),
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[...edges]
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);
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edgeLength = result.edgeLength;
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mult = result.mult;
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} while (edgeLength > 3);
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if (process.env.NODE_ENV !== 'test') {
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console.log(`That took ${i} tries`);
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console.log(mult);
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}
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return mult;
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}
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