133. Clone 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 node0
to both nodes1
and2
. - Second node is labeled as
1
. Connect node1
to node2
. - Third node is labeled as
2
. Connect node2
to node2
(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==nullptr) return nullptr; //想到用map结构难一点 unordered_map<const UndirectedGraphNode*, UndirectedGraphNode*> copied; //用map记录每一个node是否复制 clone(node, copied); return copied[node]; } static UndirectedGraphNode* clone(const UndirectedGraphNode* node, unordered_map<const UndirectedGraphNode*, UndirectedGraphNode*>& copied){ if(copied.find(node)!=copied.end()) return copied[node]; //有该节点直接返回(basecase:以自己为邻居) UndirectedGraphNode* new_node = new UndirectedGraphNode(node->label); //map中没有该label值,申请新的节点存储原图节点 copied[node] = new_node; for(auto nbr:node->neighbors) //深度遍历该节点的邻居 new_node->neighbors.push_back(clone(nbr,copied)); return new_node; } };