84 lines
2.7 KiB
C++
84 lines
2.7 KiB
C++
// Source : https://oj.leetcode.com/problems/clone-graph/
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// Author : Hao Chen
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// Date : 2014-10-12
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/**********************************************************************************
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*
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* Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.
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*
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* OJ's undirected graph serialization:
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*
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* Nodes are labeled uniquely.
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*
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* We use # as a separator for each node, and , as a separator for node label and each neighbor of the node.
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*
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* As an example, consider the serialized graph {0,1,2#1,2#2,2}.
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*
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* The graph has a total of three nodes, and therefore contains three parts as separated by #.
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*
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* First node is labeled as 0. Connect node 0 to both nodes 1 and 2.
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* Second node is labeled as 1. Connect node 1 to node 2.
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* Third node is labeled as 2. Connect node 2 to node 2 (itself), thus forming a self-cycle.
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*
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* Visually, the graph looks like the following:
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*
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* 1
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* / \
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* / \
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* 0 --- 2
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* / \
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* \_/
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*
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*
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**********************************************************************************/
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/**
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* Definition for undirected graph.
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* struct UndirectedGraphNode {
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* int label;
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* vector<UndirectedGraphNode *> neighbors;
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* UndirectedGraphNode(int x) : label(x) {};
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* };
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*/
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class Solution {
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public:
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UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
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if (node == NULL) return NULL;
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//create a map, key is source node, value is clone node.
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map<UndirectedGraphNode*, UndirectedGraphNode*> cloneMap;
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//using queue for breadth first search
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queue<UndirectedGraphNode*> q;
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q.push(node);
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//clone the root
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UndirectedGraphNode* cloneNode = new UndirectedGraphNode(node->label);
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cloneMap[node] = cloneNode;
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//breadth first search
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while(!q.empty()){
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UndirectedGraphNode* n = q.front();
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q.pop();
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//for each neighbors
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for(int i=0; i<n->neighbors.size(); i++){
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UndirectedGraphNode* neighbor= n->neighbors[i];
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//not existed in cloneMap
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if (cloneMap.find(neighbor)==cloneMap.end()){
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//clone a node
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UndirectedGraphNode* newNode = new UndirectedGraphNode(neighbor->label);
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cloneMap[n]->neighbors.push_back(newNode);
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cloneMap[neighbor] = newNode;
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//put the neighbors into the queue
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q.push(neighbor);
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}else{
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cloneMap[n]->neighbors.push_back(cloneMap[neighbor]);
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}
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}
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}
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return cloneNode;
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}
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};
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