LeetCode--clone-graph

题目描述

Clone an undirected graph. Each node in the graph contains alabeland a list of itsneighbors.

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 as0. Connect node0to both nodes1and2.
Second node is labeled as1. Connect node1to node2.
Third node is labeled as2. Connect node2to node2(itself), thus forming a self-cycle.

Visually, the graph looks like the following:

1
/ \
/   \
0 --- 2
/ \
\_/

bfs：

class Solution {
public:
UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
if (!node) return NULL;
UndirectedGraphNode* copy = new UndirectedGraphNode(node -> label);
mp[node] = copy;
queue<UndirectedGraphNode*> toVisit;
toVisit.push(node);
while (!toVisit.empty()) {
UndirectedGraphNode* cur = toVisit.front();
toVisit.pop();
for (UndirectedGraphNode* neigh : cur -> neighbors) {
if (mp.find(neigh) == mp.end()) {
UndirectedGraphNode* neigh_copy = new UndirectedGraphNode(neigh -> label);
mp[neigh] = neigh_copy;
toVisit.push(neigh);
}
mp[cur] -> neighbors.push_back(mp[neigh]);
}
}
return copy;
}
private:
unordered_map<UndirectedGraphNode*, UndirectedGraphNode*> mp;

dfs：

class Solution {
public:
UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
if (!node) return NULL;
if (mp.find(node) == mp.end()) {
mp[node] = new UndirectedGraphNode(node -> label);
for (UndirectedGraphNode* neigh : node -> neighbors)
mp[node] -> neighbors.push_back(cloneGraph(neigh));
}
return mp[node];
}
private:
unordered_map<UndirectedGraphNode*, UndirectedGraphNode*> mp;
};