<p>You are given an integer <code>n</code>, the number of nodes in a directed graph where the nodes are labeled from <code>0</code> to <code>n - 1</code>. Each edge is red or blue in this graph, and there could be self-edges and parallel edges.</p>

<p>You are given two arrays <code>redEdges</code> and <code>blueEdges</code> where:</p>

<ul>
	<li><code>redEdges[i] = [a<sub>i</sub>, b<sub>i</sub>]</code> indicates that there is a directed red edge from node <code>a<sub>i</sub></code> to node <code>b<sub>i</sub></code> in the graph, and</li>
	<li><code>blueEdges[j] = [u<sub>j</sub>, v<sub>j</sub>]</code> indicates that there is a directed blue edge from node <code>u<sub>j</sub></code> to node <code>v<sub>j</sub></code> in the graph.</li>
</ul>

<p>Return an array <code>answer</code> of length <code>n</code>, where each <code>answer[x]</code> is the length of the shortest path from node <code>0</code> to node <code>x</code> such that the edge colors alternate along the path, or <code>-1</code> if such a path does not exist.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> n = 3, redEdges = [[0,1],[1,2]], blueEdges = []
<strong>Output:</strong> [0,1,-1]
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> n = 3, redEdges = [[0,1]], blueEdges = [[2,1]]
<strong>Output:</strong> [0,1,-1]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= n &lt;= 100</code></li>
	<li><code>0 &lt;= redEdges.length,&nbsp;blueEdges.length &lt;= 400</code></li>
	<li><code>redEdges[i].length == blueEdges[j].length == 2</code></li>
	<li><code>0 &lt;= a<sub>i</sub>, b<sub>i</sub>, u<sub>j</sub>, v<sub>j</sub> &lt; n</code></li>
</ul>

class Solution {
public:
vector<list<int> >redGraph;
vector<list<int> >blueGraph;
int f(int j,int n,deque<pair<int,int>>&pq){
    vector<bool>visitedRed(n,false);
    vector<bool>visitedBlue(n,false);
    visitedRed[0] = true;
    visitedBlue[0] = true;
    int ans = 0;
    while(!pq.empty()){
        int k = pq.size();
        while(k--){
            auto idx = pq.front();
            pq.pop_front();
            if(idx.second==0){
                for(auto &i:redGraph[idx.first]){
                    if(i==j) return ans+1;
                    if(!visitedRed[i]){
                        visitedRed[i] = true;
                        pq.push_back({i,1});
                    }
                }
            }
            else{
                for(auto &i:blueGraph[idx.first]){
                    if(i==j) return ans+1;
                    if(!visitedBlue[i]){
                        visitedBlue[i] = true;
                        pq.push_back({i,0});
                    }
                }
            }
        }
        ans++;
    }
    return -1;
}
vector<int> shortestAlternatingPaths(int n, vector<vector<int>>& redEdges, vector<vector<int>>& blueEdges){
    redGraph.resize(n,list<int>());
    blueGraph.resize(n,list<int>());
    for(auto &i:redEdges){
        redGraph[i[0]].push_back(i[1]);
    }        
    for(auto &i:blueEdges){
        blueGraph[i[0]].push_back(i[1]);
    }
    vector<int>ans(n,INT_MAX);
    ans[0] = 0;
    for(int i=1;i<n;i++){
        deque<pair<int,int>>pq;
        pq.push_back({0,0});
        ans[i] = f(i,n,pq);
        pq.clear();pq.push_back({0,1});
        int a = f(i,n,pq);
        if(a != -1){
            if(ans[i]==-1) ans[i]=a;
            else ans[i] = min(ans[i],a);
        } 
    }
    return ans;        
}
};
24636