/** * 图的广度优先遍历 **/
void bfs(vector<vector<int> >& g, int s) {
    queue<int> q;
    q.push(s);
    unordered_set<int> visited;
    visited.insert(s);
    while (!q.empty()) {
        int cur = q.front();
        cout<<cur<<",";
        q.pop();
        for (int i = 0; i < g.size(); ++i) {
            if (g[cur][i] > 0 && visited.count(i) == 0) {
                q.push(i); 
                visited.insert(i);   
            }
        }
    }
    cout<<endl;
}
/** * 图的深度优先遍历 **/
void dfs_inner(vector<vector<int> >& g, int s, unordered_set<int>& visited) {
    visited.insert(s);//一定在这里着色
    cout<<s<<endl;
    for (int i = 0; i < g.size(); ++i) {
        if (visited.count(i) == 0 && g[s][i] > 0) {
            dfs_inner(g, i, visited);
        }
    }
}
void dfs(vector<vector<int> >& g) {
    unordered_set<int> visited;
    for (int i = 0; i < g.size(); ++i) {
        if (visited.count(i) == 0) {
            dfs_inner(g, i, visited);
        }
    }
}