31:[{"id":"5297b37507c7b9d29a102dff26b6ea4f0f0e620a8b4a395410ba4e93ec7073fded94cb770b647c256397f95a5f087089a5a3337eae5dab0584be4a6736599d38","href":"https://static.observableusercontent.com/files/5297b37507c7b9d29a102dff26b6ea4f0f0e620a8b4a395410ba4e93ec7073fded94cb770b647c256397f95a5f087089a5a3337eae5dab0584be4a6736599d38","name":"input01.txt","type":"text/plain","lastModified":1670636133877.111,"size":8400}] 2f:{"title":"2022 Advent of Code • Day 09 • 🪢 Rope Bridge","cells":[{"id":0,"value":"# 2022 Advent of Code • [Day 09](https://adventofcode.com/2022/day/9) • 🪢 Rope Bridge","pinned":false,"hidden":false,"mode":"md"},{"id":215,"value":"I declared time bankruptcy for the second part of Day 9.","pinned":false,"hidden":false,"mode":"md"},{"id":84,"value":"**How many positions does the tail of the rope visit at least once**? ${d3.format(\",\")(_.uniq(tailMoves.map((d) => d.join())).length)}","pinned":false,"hidden":false,"mode":"md"},{"id":78,"value":"viewof source = Inputs.radio([\"Test input\", \"Puzzle input\"], {label: \"Select source:\", value: \"Test input\"})","pinned":false,"hidden":false,"mode":"ojs"},{"id":13,"value":"input = (source == \"Test input\" ? input00 : input01).split(\"\\n\").map((line) => {\n const [dir, n] = line.split(\" \");\n return { dir: dir, n: parseInt(n) };\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":41,"value":"headMoves = {\n var x = 0,\n y = 0;\n\n return input\n .flatMap((move) => {\n switch (move.dir) {\n case \"L\":\n return _.range(0, move.n).map((_) => [x--, y]);\n case \"R\":\n return _.range(0, move.n).map((_) => [x++, y]);\n case \"U\":\n return _.range(0, move.n).map((_) => [x, y++]);\n case \"D\":\n return _.range(0, move.n).map((_) => [x, y--]);\n }\n })\n .concat([[x, y]]);\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":59,"value":"tailMoves = {\n var tailX = 0,\n tailY = 0;\n\n return headMoves.map(([headX, headY]) => {\n if (\n !(\n headX - 1 <= tailX &&\n tailX <= headX + 1 &&\n headY - 1 <= tailY &&\n tailY <= headY + 1\n )\n ) {\n tailX += headX > tailX ? 1 : headX < tailX ? -1 : 0;\n tailY += headY > tailY ? 1 : headY < tailY ? -1 : 0;\n }\n return [tailX, tailY];\n });\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":128,"value":"function tailMove(headX, headY) {\n var tailX = 0,\n tailY = 0;\n\n if (\n !(\n headX - 1 <= tailX &&\n tailX <= headX + 1 &&\n headY - 1 <= tailY &&\n tailY <= headY + 1\n )\n ) {\n tailX += headX > tailX ? 1 : headX < tailX ? -1 : 0;\n tailY += headY > tailY ? 1 : headY < tailY ? -1 : 0;\n }\n return [tailX, tailY];\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":6,"value":"## Inputs","pinned":false,"hidden":false,"mode":"md"},{"id":8,"value":"input00 = `R 4\nU 4\nL 3\nD 1\nR 4\nD 1\nL 5\nR 2`","pinned":false,"hidden":false,"mode":"ojs"},{"id":23,"value":"input01 = (await FileAttachment(\"input01.txt\").text()).trim()","pinned":true,"hidden":false,"mode":"ojs"}],"files":"$W31","stdlib":"1","titling":"auto"}