<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<int> shortestAlternatingPaths(int n, vector<vector<int>>& redEdges, vector<vector<int>>& blueEdges) {
        

        // 0 red
        // 1 blue
        unordered_map<int,list<pair<int,int>>> adjList;
        for(auto &i : redEdges){
            adjList[i[0]].push_back({i[1],0});
        }
        for(auto &i : blueEdges){
            adjList[i[0]].push_back({i[1],1});
        }

        queue<vector<int>> q;
        q.push({0,0,-1,-1}); // node curr_dist prevNode color
        unordered_map<int,unordered_map<int,unordered_map<int,bool>>> visited;
        vector<int> distance(n,INT_MAX);
        distance[0] = 0;
        visited[0][-1][-1] =  true;

        while(!q.empty()){

            auto fNode = q.front();
            int node = fNode[0];
            int dist = fNode[1];
            int prevNode = fNode[2];
            int prevColor = fNode[3];

            if(distance[node]>dist){
                distance[node] = dist;
            }

            q.pop();

            for(auto &i : adjList[node]){

                if(prevColor==-1){

                    if(!visited[i.first][node][i.second]){
                        q.push({i.first,dist + 1 , node , i.second});
                        visited[i.first][node][i.second] = true;
                    }


                }else{

                    if(prevColor!=i.second){
                        if(!visited[i.first][node][i.second]){
                            q.push({i.first,dist + 1 , node , i.second});
                            visited[i.first][node][i.second] = true;
                        }
                    }
                }



            }

        }

        for(int i =0 ; i<distance.size() ; i++){

            if(distance[i]==INT_MAX){

                distance[i] = -1;

            }


        }

        return distance;
        



    }
};
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