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154 lines
3.7 KiB
154 lines
3.7 KiB
import { readFileSync } from 'node:fs'; |
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const input = readFileSync('input', 'utf-8'); |
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const [stackInput, movementInput] = input.split('\n\n', 2); |
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// Parse movements |
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const movements = movementInput |
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.split('\n') |
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.filter(movement => movement) |
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.map(movement => { |
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const match = movement.match(/move (\d+) from (\d+) to (\d+)/); |
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if (!match) { |
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throw new Error(`Invalid movement: ${movement}`); |
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} |
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return { |
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count: parseInt(match[1]), |
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from: parseInt(match[2]), |
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to: parseInt(match[3]) |
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} |
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}); |
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// Parse stacks |
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const stackInputLines = stackInput.split('\n'); |
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const columnDelimiter = ' '; |
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const columnPositions = stackInputLines |
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// Locate delimiter positions |
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.map(line => { |
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const positions = []; |
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let pos = -1; |
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while (true) { |
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pos = line.indexOf(columnDelimiter, pos + 1); |
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if (pos === -1) { |
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break; |
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} |
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positions.push(pos); |
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} |
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return positions; |
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}) |
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.reduce((commonPositions, positions) => |
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commonPositions.filter( |
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pos => positions.includes(pos) |
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) |
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); |
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const columns = new Array(columnPositions.length + 1) |
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.fill(0) |
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.map(column => []); |
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for (const line of [...stackInputLines].reverse()) { |
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for (let i = 0; i <= columnPositions.length; i++) { |
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const start = (columnPositions[i - 1] ?? -1) + 1; |
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const end = columnPositions[i] ?? line.length; |
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const value = line.slice(start, end); |
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columns[i].push(value); |
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} |
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} |
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class Stack { |
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constructor(number, crates) { |
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this.number = number; |
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this.crates = crates; |
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} |
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get topCrate() { |
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return this.crates[this.crates.length - 1]; |
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} |
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move(count, toStack) { |
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this._checkMoveCount(count); |
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toStack.crates.push(...this.crates.splice(-count)); |
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} |
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moveIndividually(count, toStack) { |
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this._checkMoveCount(count); |
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toStack.crates.push(...this.crates.splice(-count).reverse()); |
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} |
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_checkMoveCount(count) { |
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if (count > this.crates.length) { |
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throw new Error( |
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`Tried to move ${count} crates from a stack containing: ` + |
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`${this.crates.length}` |
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); |
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} |
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} |
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} |
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function buildStacks() { |
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return new Map(columns |
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.map(column => column |
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.map(cell => cell.trim()) |
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.filter(cell => cell) |
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) |
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.map(column => { |
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if (column.length < 1) { |
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throw new Error('Invalid column'); |
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} |
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const number = parseInt(column[0]); |
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if (isNaN(number)) { |
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throw new Error(`Invalid column number: ${number}`); |
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} |
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const crates = column |
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.slice(1) |
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.map(crate => crate.replaceAll(/\[?\]?/g, '')); |
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return new Stack(number, crates); |
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}) |
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.map(stack => [stack.number, stack]) |
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); |
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} |
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function getTopCrates(stacks) { |
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return [...stacks.keys()] |
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.sort() |
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.map(number => stacks.get(number).topCrate) |
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.reduce((crates, crate) => crates + crate); |
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} |
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function runSimulation(simulationCb) { |
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for (const movement of movements) { |
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const fromStack = stacks.get(movement.from); |
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if (!fromStack) { |
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throw new Error(`Tried to move from unknown stack: ${movement.from}`); |
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} |
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const toStack = stacks.get(movement.to); |
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if (!toStack) { |
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throw new Error(`Tried to move to unknown stack: ${movement.to}`); |
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} |
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simulationCb(movement.count, fromStack, toStack); |
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} |
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} |
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let stacks; |
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let topCrates; |
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// CrateMover 9000 Simulation |
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stacks = buildStacks(); |
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runSimulation((count, fromStack, toStack) => |
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fromStack.moveIndividually(count, toStack) |
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); |
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topCrates = getTopCrates(stacks); |
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console.log(`Top crates after CrateMover 9000 sort: ${topCrates}`); |
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// CrateMover 9001 Simulation |
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stacks = buildStacks(); |
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runSimulation((count, fromStack, toStack) => |
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fromStack.move(count, toStack) |
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); |
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topCrates = getTopCrates(stacks); |
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console.log(`Top crates after CrateMover 9001 sort: ${topCrates}`);
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