LintCode "Route Between Two Nodes in Graph"

DFS ended up with TLE. Only BFS works.

/**
 * Definition for Directed graph.
 * struct DirectedGraphNode {
 *     int label;
 *     vector<DirectedGraphNode *> neighbors;
 *     DirectedGraphNode(int x) : label(x) {};
 * };
 */
class Solution {
public:
    /**
     * @param graph: A list of Directed graph node
     * @param s: the starting Directed graph node
     * @param t: the terminal Directed graph node
     * @return: a boolean value
     */
    bool bfs(DirectedGraphNode*s, DirectedGraphNode* t)
    {
        unordered_set<DirectedGraphNode*> visited;
        
        queue<DirectedGraphNode*> q;
        q.push(s);
        while(!q.empty())
        {
            auto pt = q.front(); q.pop();
            if(pt->label == t->label) return true;
            visited.insert(pt);
            
            for(auto c : pt->neighbors)
            {
                if(visited.find(c) == visited.end())
                    q.push(c);
            }
        }
        return false;
    }
    
    bool hasRoute(vector<DirectedGraphNode*> graph,
                  DirectedGraphNode* s, DirectedGraphNode* t) {
                         
        unordered_set<DirectedGraphNode*> visiteds;                      
        visiteds.insert(s);
        bool b1 = bfs(s, t);
        if(b1) return true;
        
        visiteds.clear();
        visiteds.insert(t);
        return bfs(s, t);
    }
};

View Code