LeetCode - Clone Graph

最新推荐文章于 2022-01-22 13:53:54 发布

yangyuwei11

最新推荐文章于 2022-01-22 13:53:54 发布

阅读量406

点赞数

CC 4.0 BY-SA版权

分类专栏： LeetCode

本文链接：https://blog.youkuaiyun.com/yangyuwei11/article/details/39345193

LeetCode 专栏收录该内容

121 篇文章

订阅专栏

本文介绍了一种用于克隆无向图的算法实现。该算法通过广度优先搜索遍历原始图的所有节点，并创建相应的副本节点。文章详细展示了如何处理节点的邻居关系以及自我循环等问题。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.

OJ's undirected graph serialization:

Nodes are labeled uniquely.

We use # as a separator for each node, and , as a separator for node label and each neighbor of the node.

As an example, consider the serialized graph {0,1,2#1,2#2,2}.

The graph has a total of three nodes, and therefore contains three parts as separated by #.

First node is labeled as 0. Connect node 0 to both nodes 1 and 2.
Second node is labeled as 1. Connect node 1 to node 2.
Third node is labeled as 2. Connect node 2 to node 2 (itself), thus forming a self-cycle.

Visually, the graph looks like the following:

       1
      / \
     /   \
    0 --- 2
         / \
         \_//**
 * Definition for undirected graph.
 * struct UndirectedGraphNode {
 *     int label;
 *     vector<UndirectedGraphNode *> neighbors;
 *     UndirectedGraphNode(int x) : label(x) {};
 * };
 */
class Solution {
public:
    UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
        if(node==NULL){
            return node;
        }
        queue<UndirectedGraphNode* > nodeQueue;
        map<int,UndirectedGraphNode*> newNodeMap;
        map<int,bool> visitedMap;
         
        UndirectedGraphNode *newNode=new UndirectedGraphNode(node->label);
        newNodeMap[node->label]=newNode;
        visitedMap[node->label]=false;
        nodeQueue.push(node);
         
        while(!nodeQueue.empty()){
            UndirectedGraphNode* &tmp=nodeQueue.front();
            
            int label = tmp->label;
            vector<UndirectedGraphNode*> &neighbors= tmp->neighbors;
            nodeQueue.pop();
            
            if(visitedMap[label]==true){
                continue;
            }
            visitedMap[label]=true;
            
            map<int,UndirectedGraphNode*>::iterator nodeIter= newNodeMap.find(label);
            
            for(vector<UndirectedGraphNode*>::iterator iter=neighbors.begin();iter!=neighbors.end();iter++){
                int neighborLabel = (*iter)->label;
                map<int,UndirectedGraphNode*>::iterator mapIter= newNodeMap.find(neighborLabel);
                UndirectedGraphNode *neighborNode = NULL;
                
                if(mapIter==newNodeMap.end()){
                    neighborNode = new UndirectedGraphNode(neighborLabel);
                    newNodeMap[neighborLabel]=neighborNode;
                }else{
                    neighborNode = mapIter->second;
                }
                
                nodeIter->second->neighbors.push_back(neighborNode);
                
                nodeQueue.push(*iter);
            }
            
        }
        return newNode;
        
    }
};