<p>We want to split a group of <code>n</code> people (labeled from <code>1</code> to <code>n</code>) into two groups of <strong>any size</strong>. Each person may dislike some other people, and they should not go into the same group.</p>

<p>Given the integer <code>n</code> and the array <code>dislikes</code> where <code>dislikes[i] = [a<sub>i</sub>, b<sub>i</sub>]</code> indicates that the person labeled <code>a<sub>i</sub></code> does not like the person labeled <code>b<sub>i</sub></code>, return <code>true</code> <em>if it is possible to split everyone into two groups in this way</em>.</p>

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

<pre>
<strong>Input:</strong> n = 4, dislikes = [[1,2],[1,3],[2,4]]
<strong>Output:</strong> true
<strong>Explanation:</strong> The first group has [1,4], and the second group has [2,3].
</pre>

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

<pre>
<strong>Input:</strong> n = 3, dislikes = [[1,2],[1,3],[2,3]]
<strong>Output:</strong> false
<strong>Explanation:</strong> We need at least 3 groups to divide them. We cannot put them in two groups.
</pre>

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

<ul>
	<li><code>1 &lt;= n &lt;= 2000</code></li>
	<li><code>0 &lt;= dislikes.length &lt;= 10<sup>4</sup></code></li>
	<li><code>dislikes[i].length == 2</code></li>
	<li><code>1 &lt;= a<sub>i</sub> &lt; b<sub>i</sub> &lt;= n</code></li>
	<li>All the pairs of <code>dislikes</code> are <strong>unique</strong>.</li>
</ul>

class Solution {
public:
    bool possibleBipartition(int n, vector<vector<int>>& dislikes) {
        vector<vector<int>>adj(n+1, vector<int>());
        for(int x=0;x<dislikes.size();x++){
            adj[dislikes[x][0]].push_back(dislikes[x][1]);
            adj[dislikes[x][1]].push_back(dislikes[x][0]);
        }
        vector<int> visited(n+1, -1);
        for(int x =1;x<=n;x++){
            if(visited[x] != -1){
                continue;
            }
            visited[x] = 1;
            queue<int> q;
            q.push(x);
            if(!bfs(adj, x, visited, q)){
                return false;
            }
        }
        return true;

    }

    bool bfs(vector<vector<int>>& adj, int start,  vector<int>& visited, queue<int>& q){
        while(!q.empty()){
            int start = q.front();
            q.pop();
            for(int x = 0;x<adj[start].size();x++){
                int node = adj[start][x];
                cout<<node<<endl;
                if(visited[node]==-1){
                    visited[node] = 1-visited[start];
                    q.push(node);
                }else if(visited[node] == visited[start]){
                    return false;
                }
                
            }
        }
        return true;
    }
};
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