Node.js

export class Node {
    constructor(val, neighbors) {
        this.val = val === undefined ? 0 : val;
        this.neighbors = neighbors === undefined ? [] : neighbors;
    }

    static parse(edges) {
        const nodeMap = new Map();

        // 创建节点
        const getNode = (val) => {
            if (!nodeMap.has(val)) {
                const newNode = new Node(val);
                nodeMap.set(val, newNode);
            }
            return nodeMap.get(val);
        };

        // 连接节点
        edges.forEach((neighbors, index) => {
            const val = index + 1;
            const currentNode = getNode(val);
            neighbors.forEach((neighborVal) => {
                const neighborNode = getNode(neighborVal);
                currentNode.neighbors.push(neighborNode);
            });
        });

        return nodeMap.size > 0 ? nodeMap.values().next().value : null;
    }

    static toArray(node) {
        if (!node) return [];

        const visited = new Set();
        const result = [];

        const dfs = (currentNode) => {
            if (visited.has(currentNode.val)) return;

            const { neighbors, val } = currentNode;
            visited.add(val);
            result.push(neighbors.map(({ val }) => val));
            currentNode.neighbors.forEach((neighbor) => {
                dfs(neighbor);
            });
        };

        dfs(node);

        return result;
    }
}