aoc-2023/day_8/check.ts

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2024-12-09 22:41:02 +09:00
type Node = { name: string, left: string, right: string };
const input = await Deno.readTextFile("input.txt");
const lines = input.split("\n").map(x => x.trim()).filter(x => x.length > 0);
const instructions = lines[0];
const nodes = lines.splice(1).map(x=> {
const m = /(\w+)\s*=\s*\(\s*(\w+)\s*,\s*(\w+)\s*\)/.exec(x);
if (!m){
throw new Error("Invalid line: " + x);
}
return {name: m[1], left: m[2], right: m[3]};
});
console.log(instructions, nodes);
const map = new Map<string, Node>();
for (const node of nodes){
map.set(node.name, node);
}
function stepInst(node: Node, instruction: string){
if (instruction === "R"){
return node.right
} else {
return node.left
}
}
let step = 0;
let current = nodes;
if (!current){
throw new Error("Invalid input");
}
const a = new Map<string, string[]>();
nodes.forEach(x => {
a.set(x.name, [x.name]);
});
// brute force
while (step < instructions.length){
const instruction_index = step % instructions.length;
const instruction = instructions[instruction_index];
//execute
current = current.map(x => {
const next = stepInst(x, instruction);
return map.get(next)!
});
nodes.forEach((x,i) => {
a.get(x.name)?.push(current[i].name);
})
step++;
}
await Deno.writeTextFile("s.json", JSON.stringify(current.map((x,i) => {
return {
prev: nodes[i].name,
name: x.name,
progress: a.get(x.name),
}
}), null, 2));