57 lines
1.7 KiB
TypeScript
57 lines
1.7 KiB
TypeScript
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import fs from "fs";
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export const hash = (input: string): number => {
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const parts = input.split('');
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let hash = 0;
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for (let i = 0; i < parts.length; i++) {
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hash += parts[i].charCodeAt(0);
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hash *= 17;
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hash %= 256;
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}
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return hash;
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}
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export const hashSum = (input: string): number => {
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return input.split(',').reduce((sum, part) => sum + hash(part), 0);
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}
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const focusingPower = (boxNumber: number, slot: number, value: number): number => {
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return (1 + boxNumber) * (1 + slot) * value;
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}
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export const totalFocusingPower = (input: string): number => {
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const boxes: [string, number][][] = new Array(256).fill(0).map(() => []);
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input.split(',').forEach(part => {
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if (part.includes('=')) {
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const [label, value] = part.split('=');
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const box = hash(label);
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const index = boxes[box].findIndex(([l]) => l === label);
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boxes[hash(label)].splice(index === -1 ? boxes[box].length : index, 1, [label, parseInt(value)]);
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} else {
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const [label] = part.split('-');
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let box = hash(label);
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const index = boxes[box].findIndex(([l]) => l === label);
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if (index !== -1) {
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boxes[box].splice(index, 1);
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}
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}
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});
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return boxes.reduce(
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(sum, box, boxIndex) =>
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sum + box.reduce(
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(total, [label, value], slot) => {
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return total + focusingPower(boxIndex, slot, value)
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},
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0
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),
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0
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);
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}
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export const runDayFifteen = () => {
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const input = fs.readFileSync('./inputs/day_fifteen_input.txt', 'utf-8').trimEnd();
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console.log('Day Fifteen output:', totalFocusingPower(input));
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}
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