LeetCode_Copy Graph

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 NULL;        }        //储存值和指针之间的对应关系        unordered_map <int ,UndirectedGraphNode * > labelPointorMap;        typedef pair<int ,UndirectedGraphNode *>  labelPointor;        typedef unordered_map<int ,UndirectedGraphNode * >::iterator mapIter;        //广度优先Copy队列        queue <UndirectedGraphNode * > BFSqueue;        //复制完成标志map        unordered_map <int,int> labelCopyFlagMap;        typedef pair <int,int> labelCopy;        typedef unordered_map <int,int>::iterator laCoIter;        UndirectedGraphNode *ptemp, *pCloneTemp;        BFSqueue.push(node);        while (!BFSqueue.empty())        {            ptemp=BFSqueue.front();            BFSqueue.pop();            //复制Label            mapIter mIter=labelPointorMap.find(ptemp->label);            if (mIter==labelPointorMap.end())            {                pCloneTemp=new UndirectedGraphNode(ptemp->label);                labelPointorMap.insert(labelPointor(ptemp->label,pCloneTemp));                labelCopyFlagMap.insert(labelCopy(ptemp->label,1));//标记当前node已经完成深度copy            }            else            {                pCloneTemp=mIter->second;                laCoIter iIter=labelCopyFlagMap.find(pCloneTemp->label);                //防止两个节点之间有多条边相连，导致其中一个节点被多次复制                if (iIter->second==1)                {                    continue;                }                else                {                    iIter->second=1;                }            }            //复制neighbour            vector<UndirectedGraphNode*>::iterator iter=ptemp->neighbors.begin();            UndirectedGraphNode *pCloneNeighborTemp;            for(;iter<ptemp->neighbors.end();iter++)            {                mIter=labelPointorMap.find((*iter)->label);                if (mIter==labelPointorMap.end())                {                    pCloneNeighborTemp=new UndirectedGraphNode((*iter)->label);                    labelPointorMap.insert(labelPointor((*iter)->label,pCloneNeighborTemp));                    labelCopyFlagMap.insert(labelCopy(pCloneNeighborTemp->label,0));//标记对应节点没有进行深度copy操作                }                else                {                    pCloneNeighborTemp=mIter->second;                }                pCloneTemp->neighbors.push_back(pCloneNeighborTemp);                //将未完成深度Copy的节点放入队列                laCoIter lIter=labelCopyFlagMap.find(pCloneNeighborTemp->label);                if (lIter->second==0)                {                    BFSqueue.push((*iter));                }            }        }        mapIter mIter=labelPointorMap.find(node->label);        return mIter->second;    }};