<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 DSU{
public:
    vector<int> parent;
    vector<int> rank;

    DSU(int sz): parent(sz),rank(sz){
        for(int i=0;i<sz;i++){
            parent[i]=i;
            rank[i]=0;
        }
    }

    int find(int x){
        if(parent[x]!=x){
            parent[x]=find(parent[x]);
        }

        return parent[x];
    }

    bool unionSet(int a, int b){
        int rootx=find(a);
        int rooty=find(b);

        if(rootx==rooty)return false;
        if(rank[rootx]<rank[rooty]){
            parent[rootx]=rooty;
        }else if(rank[rooty]<rank[rootx]){
            parent[rooty]=rootx;
        }else{
            parent[rooty]=rootx;
            rank[rootx]+=1;
        }

        return true;
    }
};

class Solution {
public:
    bool isSimilar(string a, string b){
        int n=a.size();
        int diff=0;
        for(int i=0;i<n;i++){
            if(a[i]!=b[i]){
                diff++;
                if(diff>2)return false;
            }
        }

        return true;
    }

    int numSimilarGroups(vector<string>& strs) {
        int n=strs.size();

        int res=n;
        DSU dsu(n);

        for(int i=0;i<n-1;i++){
            for(int j=1;j<n;j++){
                if(isSimilar(strs[i],strs[j])&& dsu.unionSet(i,j)){
                    res--;
                }
            }
        }

        return res;
    }
};
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