<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:
    void dfs(string node,unordered_map<string,unordered_set<string>>& adj,unordered_map<string,int>& vis){
        if(vis[node]) return;
        vis[node]=1;
        for(auto it:adj[node]) dfs(it,adj,vis);
        return;
    }
    int numSimilarGroups(vector<string>& s) {
    unordered_set<string> st;
        for(auto it:s) st.insert(it);
        unordered_map<string,unordered_set<string>> adj;
        for(auto it:s){
            string temp=it;
            for(int i=0;i<it.size();i++){
                for(int j=i+1;j<it.size();j++){
                    swap(it[i],it[j]);
                    if(st.find(it)!=st.end()&&it!=temp) adj[temp].insert(it);
                    swap(it[i],it[j]);
                }
            }
        }

        int ans=0;
        unordered_map<string,int> vis;
        for(auto it:s){
            if(vis.find(it)==vis.end()){ 
                dfs(it,adj,vis); ans++;
            }
        }
        return ans;
    }
};
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