83 lines
No EOL
3.6 KiB
TypeScript
83 lines
No EOL
3.6 KiB
TypeScript
import { solvables } from "../main.ts";
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import type { Solvable } from "../solvable.ts";
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import { readInput } from "../utils.ts";
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class DayTwo implements Solvable {
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input = readInput('02')
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public part1(): Promise<DayTwo> {
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const reports = this.input.trim().split("\n").map(line => line.split(' ').map(level => Number.parseInt(level)))
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const slidingWindow = (levels: number[]): boolean => {
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const gradients: ("ascending" | "descending")[] = []
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let [i, j] = [0, 1]
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while (j < levels.length) {
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// is unsafe if ascent / descend bigger than 3 or smaller than 1
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const diff = Math.abs(levels[i] - levels[j])
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if (diff > 3 || diff < 1) {
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return false
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}
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// calculate positive or negative gradient
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if (levels[i] < levels[j]) {
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gradients.push("ascending")
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} else if (levels[i] > levels[j]) {
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gradients.push("descending")
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}
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i++
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j++
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}
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// is safe and constant gradient?
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const constantGradient = gradients.every((gradient) => gradient === "ascending") || gradients.every((gradient) => gradient === "descending")
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return constantGradient
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}
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const result = reports.map(levels => slidingWindow(levels)).filter(level_safe => level_safe === true).length
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console.log(result)
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return new Promise(() => this)
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}
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public part2(): Promise<DayTwo> {
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const reports = this.input.trim().split("\n").map(line => line.split(' ').map(level => Number.parseInt(level)))
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const slidingWindow = (levels: number[]): boolean => {
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const gradients: ("ascending" | "descending" | "stagnating")[] = []
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const diffs: number[] = []
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let [i, j] = [0, 1]
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while (j < levels.length) {
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// is unsafe if ascent / descend bigger than 3 or smaller than 1
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const diff = Math.abs(levels[i] - levels[j])
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diffs.push(diff)
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// calculate positive or negative gradient
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if (levels[i] < levels[j]) {
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gradients.push("ascending")
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} else if (levels[i] > levels[j]) {
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gradients.push("descending")
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} else {
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gradients.push("stagnating")
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}
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i++
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j++
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}
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// amount of unsafe diffs
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const unsafeDiffs = diffs.filter((diff) => diff > 3 || diff < 1).length
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// how many gradients are ascending / descending?
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const ascendingAmount = gradients.filter((gradient) => gradient === "ascending").length
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const descendingAmount = gradients.filter((gradient) => gradient === "descending").length
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// accept one unsafe diff if all gradients either ascending or descending
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if (ascendingAmount === gradients.length || descendingAmount === gradients.length && unsafeDiffs === 1) return true
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// allow for one wrong gradient
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const ascendingExceptOne = ascendingAmount >= gradients.length - 1
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const descendingExceptOne = descendingAmount >= gradients.length - 1
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return ascendingExceptOne || descendingExceptOne
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}
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const result = reports.map(levels => slidingWindow(levels)).filter(level_safe => level_safe === true).length
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console.log(result)
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return new Promise(() => this)
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}
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}
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solvables.push(new DayTwo()) |