[算法作业][LeetCode] 133. Clone Graph

[算法作业][LeetCode] 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 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
/ \
\_/

因为每一个node都需要保存到map中，保证下次需要的时候不再创建的同时，node链接的数据也能得到保留。

然后通过深搜来构造图即可。

/**
* 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;

int val = node->label;
if (dict.find(val) != dict.end()) return dict[val];

UndirectedGraphNode* root = new UndirectedGraphNode(val);
dict[val] = root;
for (int i=0; i<node->neighbors.size(); ++i) {
UndirectedGraphNode* tmp = cloneGraph(node->neighbors[i]);
if (tmp == NULL) continue;
root->neighbors.push_back(tmp);
}

return root;

}
private:
map<int, UndirectedGraphNode*> dict;
};