和龙建设局网站定制科技软件

1.题目描述

2.思路
思路一：

方法 1：BFS（广度优先搜索 + 队列）

方法 2：DFS（深度优先搜索 + 递归）



例子2：




例子3：

3.代码实现
方法一：深度优先队列+递归

class Solution {private Map<Node, Node> m = new HashMap<>();//用于存储节点到克隆节点的映射，避免重复创建节点public Node cloneGraph(Node node) {if (node == null)return null;if (m.containsKey(node))return m.get(node);//如果已经克隆，则返回该点//克隆当前节点Node clone = new Node(node.val, new ArrayList<>());m.put(node, clone);//递归克隆所有邻居for (Node neighbor : node.neighbors) {clone.neighbors.add(cloneGraph(neighbor));}return clone;}
}

方法二：深度优先队列+递归（带测试方法）

import java.util.*;class Node {public int val;public List<Node> neighbors;public Node() {val = 0;neighbors = new ArrayList<Node>();}public Node(int _val) {val = _val;neighbors = new ArrayList<Node>();}public Node(int _val, ArrayList<Node> _neighbors) {val = _val;neighbors = _neighbors;}
}class Solution10 {private Map<Node, Node> m = new HashMap<>();//用于存储节点到克隆节点的映射，避免重复创建节点public Node cloneGraph(Node node) {if (node == null)return null;if (m.containsKey(node))return m.get(node);//如果已经克隆，则返回该点//克隆当前节点Node clone = new Node(node.val, new ArrayList<>());m.put(node, clone);//递归克隆所有邻居for (Node neighbor : node.neighbors) {clone.neighbors.add(cloneGraph(neighbor));}return clone;}// 测试方法public static void main(String[] args) {// 创建测试图Node node1 = new Node(1);Node node2 = new Node(2);Node node3 = new Node(3);Node node4 = new Node(4);node1.neighbors.add(node2);node1.neighbors.add(node3);node2.neighbors.add(node1);node2.neighbors.add(node4);node3.neighbors.add(node1);node3.neighbors.add(node4);node4.neighbors.add(node2);node4.neighbors.add(node3);Solution10 solution = new Solution10();Node clonedGraph = solution.cloneGraph(node1);// 打印克隆结果System.out.println("克隆图的邻接表:");printGraph(clonedGraph, new HashSet<>());}// 辅助方法：打印图的邻接表private static void printGraph(Node node, Set<Integer> visited) {if (node == null || visited.contains(node.val)) return;visited.add(node.val);System.out.print("Node " + node.val + ": [");for (Node neighbor : node.neighbors) {System.out.print(neighbor.val + " ");}System.out.println("]");for (Node neighbor : node.neighbors) {printGraph(neighbor, visited);}}}

方法三：广度优先遍历+队列

import java.util.*;class Solution {public Node cloneGraph(Node node) {if (node == null) return null;Map<Node, Node> map = new HashMap<>();Queue<Node> queue = new LinkedList<>();// 克隆起始节点并入队Node clone = new Node(node.val, new ArrayList<>());map.put(node, clone);queue.offer(node);while (!queue.isEmpty()) {Node cur = queue.poll();  // 取出队首节点for (Node neighbor : cur.neighbors) {if (!map.containsKey(neighbor)) { // 还未克隆map.put(neighbor, new Node(neighbor.val, new ArrayList<>()));queue.offer(neighbor);}// 连接克隆的邻居map.get(cur).neighbors.add(map.get(neighbor));}}return clone;}
}