leetcode：Clone Graph

最新推荐文章于 2021-07-14 09:59:19 发布

原创最新推荐文章于 2021-07-14 09:59:19 发布 · 601 阅读

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本文介绍如何使用广度优先搜索(BFS)解决LeetCode中的克隆图问题，通过HashMap记录已访问节点，实现图结构的完全复制。

复制图的结构，直接使用BFS广度优先搜索的方法进行图的遍历

利用HashMap作为是否访问过的标记

<span style="font-size:18px;">/**
 * Definition for undirected graph.
 * class UndirectedGraphNode {
 *     int label;
 *     List<UndirectedGraphNode> neighbors;
 *     UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); }
 * };
 */
public class Solution {
    
    
    public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {
        if(node == null) return node;
        
        HashMap<Integer, UndirectedGraphNode> cloneMap = new HashMap<>();
        UndirectedGraphNode clone = new UndirectedGraphNode(node.label);
        
        LinkedList<UndirectedGraphNode> nodeQueue = new LinkedList<>();
        nodeQueue.add(node);
        
        cloneMap.put(clone.label, clone);
        
        while(!nodeQueue.isEmpty()){
            UndirectedGraphNode top = nodeQueue.pop();
            UndirectedGraphNode cloneTop = cloneMap.get(top.label);
            for(UndirectedGraphNode t : top.neighbors){
                UndirectedGraphNode cloneT = cloneMap.get(t.label);
                if(cloneT == null){
                    cloneT = new UndirectedGraphNode(t.label);
                    cloneMap.put(cloneT.label, cloneT);
                    nodeQueue.push(t);
                }
                cloneTop.neighbors.add(cloneT);
            }
        }
        return clone;
    }
    
}</span>