<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:

    bool checkSimilar(string s1, string s2) {
        int countDiff = 0;
        for(int i=0; i<s1.size(); i++) {
            if(s1[i] != s2[i]) {
                countDiff++;
            }
        }

        if(countDiff > 2) {
            return false;
        }
        return true;
    }

    vector<vector<int>> generateAdjList(vector<string>& strs, int n) {
        vector<vector<int>> adjList(n);
        for(int i=0; i<n-1; i++) {
            for(int j=i+1; j<n; j++) {
                if(checkSimilar(strs[i], strs[j])) {
                    adjList[i].push_back(j);
                    adjList[j].push_back(i);
                }
            }
        }
        return adjList;
    }

    void bfs(vector<int>& visited, vector<vector<int>>& adjList, int start) {
        queue<int> q;
        q.push(start);
        visited[start] = 1;

        while(!q.empty()) {
            int poppedNode = q.front();
            q.pop();
            for(int next: adjList[poppedNode]) {
                if(visited[next] == 0) {
                    q.push(next);
                    visited[next] = 1;
                }
            }
        }
    }

    int numSimilarGroups(vector<string>& strs) {
        int n = strs.size();
        vector<vector<int>> adjList = generateAdjList(strs, n); 
        // for(int i=0; i<adjList.size(); i++) {
        //     for(int j=0; j<adjList[i].size(); j++) {
        //         cout<<strs[adjList[i][j]]<<" ";
        //     }
        //     cout<<"#\n";
        // }     
        vector<int> visited(strs.size(), 0);
        int ans = 0;
        for(int i=0; i<n; i++) {
            if(visited[i] == 0) {
                ans++;
                bfs(visited, adjList, i);
            }
        }
        return ans;
    }
};
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