D - Takahashi Tour

D - Takahashi Tour

https://atcoder.jp/contests/abc213/tasks/abc213_d

 

思路

图数据结构存储边的关系。

DFS遍历，

对于相邻节点存储使用set。

Code

https://atcoder.jp/contests/abc213/submissions/38555258

/******************************** GRAPH START ***************************************/
// Graph class represents a directed graph
// using adjacency list representation
class Graph {
public:
    map<int, bool> visited;
    map<int, set<int> > adj;
//    vector<int> order;
 
    // function to add an edge to graph
    void addEdge(int v, int w);
 
    // DFS traversal of the vertices
    // reachable from v
    void DFS(int v);
};
 
void Graph::addEdge(int v, int w)
{
    adj[v].insert(w); // Add w to v’s list.
}
 
void Graph::DFS(int v)
{
//    cout << "------" << endl;
    // Mark the current node as visited and
    // print it
    visited[v] = true;
    cout << v << " ";
    
//    order.push_back(v);
 
    // Recur for all the vertices adjacent
    // to this vertex
    set<int>::iterator i;
    for (i = adj[v].begin(); i != adj[v].end(); ++i)
        if (!visited[*i]){
            DFS(*i);
//            order.push_back(v);
            cout << v << " ";
        }
}
 
/******************************** GRAPH END ***************************************/
 
/*
https://atcoder.jp/contests/abcxxx/tasks/abcxxx_d
*/
 
Graph gp;
int n;
 
int main()
{
    cin >> n;
    
    for(int i=0; i<n-1; i++){
        int ai, bi;
        
        cin >> ai >> bi;
        gp.addEdge(ai, bi);
        gp.addEdge(bi, ai);
    }
 
    gp.DFS(1);
    
//    for(int i=0; i<gp.order.size(); i++){
//        cout << gp.order[i] << " ";
//    }
 
    return 0;
}