<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 dfs(int node, vector<vector<int>> &adj, vector<int> &vis, unordered_map<int,int> &m){
        vis[node] = 1;
        for(int x : adj[node]){
            if(vis[x] == 0){
                m[x] = 1-m[node];
                if(!dfs(x,adj,vis,m)) return 0;
            }
            else{
                if(m[x] == m[node]) return 0;
            }
        }
        return 1;
    }
    bool possibleBipartition(int n, vector<vector<int>>& v) {
        vector<vector<int>> adj(n);
        for(auto x : v){
            adj[x[0]-1].push_back(x[1]-1);
            adj[x[1]-1].push_back(x[0]-1);
        }
        vector<int> vis(n,0);
        unordered_map<int,int> m;
        for(int i = 0; i < n; i++){
            if(vis[i] == 0){
                m[i] = 1;
                if(!dfs(i,adj,vis,m)) return 0;
            }
        }
        return 1;
    }
};
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