<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:
    vector<int> par;
    vector<int> rank;

    bool isSimilar(string a, string b) {
        vector<char> arr1;
        vector<char> arr2;

        for(int i=0; i<a.size(); i++) {
            if (a[i] != b[i]) {
                arr1.push_back(a[i]);
                arr2.push_back(b[i]);

                if (arr1.size() > 2) return false;
            }
        }

        if (arr1.size() == 2) {
            if (arr1[0] == arr2[1] && arr1[1]==arr2[0]) return true;
        }
        return false;
    }

    int find(int p) {
        while(p != par[p]) {
            p = par[par[p]];
        }
        return p;
    }

    void doUnion(int a, int b) {
        int parA = find(a);
        int parB = find(b);

        if(parA != parB) {
            if (rank[parA] > rank[parB]){
                rank[parA] += rank[parB];
                par[parB] = parA;
            } else {
                rank[parB] += rank[parA];
                par[parA] = parB;
            }
        }
    }

    int numSimilarGroups(vector<string>& strs) {
        map<string, int> mp;
        map<int, string> revMp;

        int counter = 0;
        for(auto str : strs) {
            mp[str] = counter++;
        }
        for(auto x : mp) {
            revMp[x.second] = x.first;
        }

        par = vector<int>(counter);
        rank = vector<int>(counter);

        for(int i=0; i<counter; i++) {
            par[i]=i;
            rank[i]=1;
        }

        for(int i=0; i<strs.size(); i++) {
            for(int j=i+1; j<strs.size(); j++) {
                int a = mp[strs[i]];
                int b = mp[strs[j]];

                if (isSimilar(strs[i], strs[j])) {
                    doUnion(a,b);
                }
            }
        }

        set<int> st;
        for(int i=0; i<strs.size(); i++) {
            int a =mp[strs[i]];
            int parA = find(a);
            st.insert(parA);
        }

        return st.size();
    }
};
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