<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) {
        vector<int> red[n];
        vector<int> blue[n];
        vector<int> ans(n);
        for(int i = 0; i < n; i++){
            ans[i] = -1;
        }

        for(vector<int> r : redEdges){
            red[r[0]].push_back(r[1]);
        }
        for(vector<int> b : blueEdges){
            blue[b[0]].push_back(b[1]);
        }

        queue<pair<int, bool>> q;
        bool visited[n][2];
        for(int i = 0; i < n; i++){
            for(int j = 0; j < 2; j++){
                visited[i][j] = false;
            }
        }

        pair<int, bool> curr;
        int val;
        bool color;

        q.push({0, false});//false : red
        q.push({0, true});//true : blue
        int level = 1;
        ans[0] = 0;

        int qSize;

        while(q.empty() == false){
            qSize = q.size();
            while(qSize > 0){
                qSize --;
                curr = q.front();
                q.pop();
                val = curr.first;
                color = curr.second;

                if(color == false){
                    //is red
                    for(int b : blue[val]){
                        if(visited[b][1] == false){
                            visited[b][1] = true;
                            if(ans[b] == -1){
                                ans[b] = level;
                            }
                            q.push({b, true});
                        }
                    }
                }

                else{
                    //is blue
                    for(int r : red[val]){
                        if(visited[r][0] == false){
                            visited[r][0] = true;
                            if(ans[r] == -1){
                                ans[r] = level;
                            }
                            q.push({r, false});
                        }
                    }
                }
            }
            level ++;

        }

        return ans;
    }
};
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