1059

class Solution {
public:
    const int UNVISITED=1, EXPLORED=2, VISITED=3;
    bool leadsToDestination(int n, vector<vector<int>>& edges, int source, int destination) {
        vector<vector<int>> g(n);
        for(auto edge: edges)
            g[edge[0]].push_back(edge[1]);

        vector<int> state(n, UNVISITED);
        bool cycle = false;
        dfs(source, destination, g, state, cycle);
        return !cycle;
    }

    void dfs(int source, int dest, vector<vector<int>> &g, vector<int> &state, bool &cycle){
        if(cycle) return;
        if(state[source] == EXPLORED){
            cycle = true;
            return;
        }
        state[source] = EXPLORED;
        if(!g[source].size() && source != dest){
            cycle = true;
            return;
        }
        for(auto child: g[source])
            if(state[child] != VISITED)
                dfs(child, dest, g, state, cycle);
        state[source] = VISITED;
    }
};