<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 DisjointSet{
    vector<int>rank,parent,size;
    public:
    DisjointSet(int n){
        rank.resize(n+1,0);
        parent.resize(n+1);
        size.resize(n+1);
        for(int i=0 ; i<=n ; i++){
            parent[i]=i;
            size[i]=1;
        }
    }
    int findUPar(int node){
        if(node==parent[node])return node;
        return parent[node]=findUPar(parent[node]);
    }
    void unionBySize(int u,int v){
        int ulp_u=findUPar(u);
        int ulp_v=findUPar(v);
        if(ulp_u==ulp_v)return;
        if(size[ulp_u]<size[ulp_v]){
            parent[ulp_u]=ulp_v;
            size[ulp_v]+=size[ulp_u];
        }
        else {
            parent[ulp_v]=ulp_u;
            size[ulp_u]+=size[ulp_v];
        }
    }
};

class Solution {
public:

bool isSimilar(string X,string Y){
    int n=X.size();
    
    int dif=0;
    for(int i=0;i<n;i++){
        if(X[i]!=Y[i])dif++;
    }

    if(dif==0 || dif==2)return 1;
    return 0;
}
    int numSimilarGroups(vector<string>& strs) {
        int n=strs.size(); 

        DisjointSet ds(n);

        int ans=n;
        for(int i=0;i<n;i++){
            for(int j=i+1;j<n;j++){
                string s1=strs[i];
                string s2=strs[j];

                if(isSimilar(s1,s2) && ds.findUPar(i)!=ds.findUPar(j)){
                    ds.unionBySize(i,j);
                    ans--;
                }
            }
        }

        // int cnt=0;
        // for(int i=0;i<n;i++)if(ds.findUPar(i)==i)cnt++;
        return ans;
    }
};
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