Find the Connected Component in the Undirected Graph

Find the number connected component in the undirected graph. Each node in the graph contains a label and a list of its neighbors. (a connected component (or just component) of an undirected graph is a subgraph in which any two vertices are connected to each other by paths, and which is connected to no additional vertices in the supergraph.)

http://www.lintcode.com/en/problem/find-the-connected-component-in-the-undirected-graph/

Solution

就是BFS，没啥好说的。

class Solution {
public:
    /**
     * @param nodes a array of Undirected graph node
     * @return a connected set of a Undirected graph
     */
    vector<vector<int>> connectedSet(vector<UndirectedGraphNode*>& nodes) {
        // Write your code here
        vector<vector<int> > result;
        unordered_set<UndirectedGraphNode*> is_visited;
        vector<int> component;
        for(auto const& node : nodes) {
            if(is_visited.find(node) == is_visited.end()) {
                bsf(node, is_visited, component);
                sort(component.begin(), component.end());
                result.emplace_back(component);
                component.clear();
            }
        }
        return result;
    }

    void bsf(UndirectedGraphNode* node, unordered_set<UndirectedGraphNode*> &is_visited, 
    vector<int> &records) {
        queue<UndirectedGraphNode*> myque;
        myque.emplace(node);
        is_visited.emplace(node);
        while(!myque.empty()) {
            UndirectedGraphNode *cur  = myque.front();
            myque.pop();
            records.emplace_back(cur->label);
            for(auto const& n : cur->neighbors) {
                if(is_visited.find(n) == is_visited.end()) {
                    is_visited.emplace(n);
                    myque.emplace(n);
                }
            }
        }
    }
};