<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 DisjoinSet
{
    public:
    vector<int> rank,parent;
    DisjoinSet(int n){
        rank.resize(n+1,0);
        parent.resize(n+1,0);
        for(int i=0;i<=n;i++){
            parent[i]=i;
        }
    }
    
    int findPar(int node){
        if(node==parent[node]) return node;
        return parent[node]=findPar(parent[node]);
    }
    
    void unionByRank(int u,int v){
        int up=findPar(u);
        int vp=findPar(v);
        if(up==vp) return;
        if(rank[up]>rank[vp]){
            parent[vp]=up;
        }
        else if(rank[up]<rank[vp]){
            parent[up]=vp;
        }
        else{
            parent[up]=vp;
            rank[vp]++;
        }
    }
};
class Solution {
public:
    bool isSimilar(string s,string sa){
        int c=0,n=s.size();
        for(int i=0;i<n;i++){
            if(s[i]!=sa[i]) c++;
        }
        return c==0||c==2;
        }
    int numSimilarGroups(vector<string>& strs) {
        int n=strs.size(),c=0;
        DisjoinSet ds(n); 
        for(int i=0;i<n;i++){
            for(int j=i+1;j<n;j++){
               if(ds.findPar(i)!=ds.findPar(j)&&isSimilar(strs[i],strs[j])) ds.unionByRank(i,j);
            }
        }
        for(int i=0;i<n;i++){
            if(ds.findPar(i)!=i){
                c++;
            }
        }
        return n-c;
    }
};
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