<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<vector<pair<int, int>>> adjList; // 1 for red, 0 for blue
    int BFS(int target) {
        cout << endl << "BFS FOR TARGET: " << target << endl;
        map<pair<int, int>, bool> takenEdges;
        queue<pair<int, int>> q;
        q.push({0, -1});
        for (int sz = q.size(), level = 0; !q.empty(); ++level, sz = q.size())
            while (sz--) {
                auto [node, lastEdge] = q.front();
                q.pop();
                if (node == target) {
                    cout << "found " << target << " at level " << level << endl;
                    return level;
                }
                for (auto pair : adjList[node]) {
                    auto [neighbour, edgeColor] = pair;
                    if ((edgeColor == -1 || edgeColor ^ lastEdge) &&
                        !takenEdges[{neighbour, edgeColor}]) {
                        cout << "added " << node << " " << neighbour << " "
                             << edgeColor << endl;
                        takenEdges[{neighbour, edgeColor}] = true;
                        q.push(pair);
                    }
                }
            }
        cout << "return -1" << endl;
        return -1;
    }
    vector<int> shortestAlternatingPaths(int n, vector<vector<int>>& redEdges,
                                         vector<vector<int>>& blueEdges) {
        adjList.assign(n, vector<pair<int, int>>());
        for (auto pair : redEdges)
            adjList[pair[0]].push_back({pair[1], 1});
        for (auto pair : blueEdges)
            adjList[pair[0]].push_back({pair[1], 0});

        vector<int> ans(n);
        for (int i = 0; i < n; ++i)
            ans[i] = BFS(i);
        return ans;
    }
};
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