<p>Two strings, <code>X</code> and <code>Y</code>, are considered similar if either they are identical or we can make them equivalent by swapping at most two letters (in distinct positions) within the string <code>X</code>.</p>

<p>For example, <code>&quot;tars&quot;</code>&nbsp;and <code>&quot;rats&quot;</code>&nbsp;are similar (swapping at positions <code>0</code> and <code>2</code>), and <code>&quot;rats&quot;</code> and <code>&quot;arts&quot;</code> are similar, but <code>&quot;star&quot;</code> is not similar to <code>&quot;tars&quot;</code>, <code>&quot;rats&quot;</code>, or <code>&quot;arts&quot;</code>.</p>

<p>Together, these form two connected groups by similarity: <code>{&quot;tars&quot;, &quot;rats&quot;, &quot;arts&quot;}</code> and <code>{&quot;star&quot;}</code>.&nbsp; Notice that <code>&quot;tars&quot;</code> and <code>&quot;arts&quot;</code> are in the same group even though they are not similar.&nbsp; Formally, each group is such that a word is in the group if and only if it is similar to at least one other word in the group.</p>

<p>We are given a list <code>strs</code> of strings where every string in <code>strs</code> is an anagram of every other string in <code>strs</code>. How many groups are there?</p>

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

<pre>
<strong>Input:</strong> strs = [&quot;tars&quot;,&quot;rats&quot;,&quot;arts&quot;,&quot;star&quot;]
<strong>Output:</strong> 2
</pre>

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

<pre>
<strong>Input:</strong> strs = [&quot;omv&quot;,&quot;ovm&quot;]
<strong>Output:</strong> 1
</pre>

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

<ul>
	<li><code>1 &lt;= strs.length &lt;= 300</code></li>
	<li><code>1 &lt;= strs[i].length &lt;= 300</code></li>
	<li><code>strs[i]</code> consists of lowercase letters only.</li>
	<li>All words in <code>strs</code> have the same length and are anagrams of each other.</li>
</ul>

class Solution {
public:
    bool similar( string a, string b )
    {
        int n=a.size();
        int cnt=0;
        for(int i=0;i<n;i++)
        {
            if(a[i]!=b[i])
            cnt++;
        }
        return cnt==0 || cnt == 2;
    }
    void dfs(int i, unordered_map<int,vector<int>>&adj, vector<bool>&visited )
    {
         queue<int>q;
         q.push(i);
         visited[i] =true;
         while(!q.empty())
         {
            int u =q.front();
            q.pop();
            for(auto x: adj[u])
            {
                if(!visited[x])
                {
                    q.push(x);
                    visited[x]=true;
                }
            }
         }
    }
    int numSimilarGroups(vector<string>& strs) {
        
         unordered_map<int,vector<int>>adj;
         int n=strs.size();
         for(int i=0;i<n;i++)
         {
            for(int j=i+1;j<n;j++)
            {
                  if(similar(strs[i],strs[j]))
                  {
                    adj[i].push_back(j);
                    adj[j].push_back(i);
                  }
            }
         }
         vector<bool>visited(n,false);
         int cnt=0;
         for(int i=0;i<n;i++)
         {
            if(!visited[i])
            {
              dfs(i,adj,visited);
               cnt++;
            }
           
         }
         return cnt;
    }
};
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