<p>You are given a string <code>s</code>, and an array of pairs of indices in the string&nbsp;<code>pairs</code>&nbsp;where&nbsp;<code>pairs[i] =&nbsp;[a, b]</code>&nbsp;indicates 2 indices(0-indexed) of the string.</p>

<p>You can&nbsp;swap the characters at any pair of indices in the given&nbsp;<code>pairs</code>&nbsp;<strong>any number of times</strong>.</p>

<p>Return the&nbsp;lexicographically smallest string that <code>s</code>&nbsp;can be changed to after using the swaps.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;dcab&quot;, pairs = [[0,3],[1,2]]
<strong>Output:</strong> &quot;bacd&quot;
<strong>Explaination:</strong> 
Swap s[0] and s[3], s = &quot;bcad&quot;
Swap s[1] and s[2], s = &quot;bacd&quot;
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;dcab&quot;, pairs = [[0,3],[1,2],[0,2]]
<strong>Output:</strong> &quot;abcd&quot;
<strong>Explaination: </strong>
Swap s[0] and s[3], s = &quot;bcad&quot;
Swap s[0] and s[2], s = &quot;acbd&quot;
Swap s[1] and s[2], s = &quot;abcd&quot;</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;cba&quot;, pairs = [[0,1],[1,2]]
<strong>Output:</strong> &quot;abc&quot;
<strong>Explaination: </strong>
Swap s[0] and s[1], s = &quot;bca&quot;
Swap s[1] and s[2], s = &quot;bac&quot;
Swap s[0] and s[1], s = &quot;abc&quot;
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 10^5</code></li>
	<li><code>0 &lt;= pairs.length &lt;= 10^5</code></li>
	<li><code>0 &lt;= pairs[i][0], pairs[i][1] &lt;&nbsp;s.length</code></li>
	<li><code>s</code>&nbsp;only contains lower case English letters.</li>
</ul>

class Solution {
public:
    void find_connection(vector<vector<int>>&adj, set<int>&connected_nodes, int idx, vector<int>&vis){
        connected_nodes.insert(idx);
        vis[idx] = 1;
        for(auto& ele: adj[idx]){
            if(vis[ele]==0)
                find_connection(adj,connected_nodes,ele,vis);
        }
    }

    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {

        int len = s.length();
        vector<vector<int>>adj(len);
        for(auto& ele: pairs){
            adj[ele[0]].push_back(ele[1]);
            adj[ele[1]].push_back(ele[0]);
        }
        vector<int>vis(len,0);
        vector<vector<int>> connection_matrix;
        for(int i=0; i<len; i++){
            if(vis[i]==0){
                set<int>connected_nodes;
                find_connection(adj,connected_nodes,i,vis);
                vector<int>vec;
                for(auto& ele: connected_nodes){
                    vec.push_back(ele);
                }
                sort(vec.begin(),vec.end());
                connection_matrix.push_back(vec);
            }
        }
        for(auto& vec: connection_matrix){
            vector<char> str;
            for(auto&idx: vec){
                str.push_back(s[idx]);
            }
            sort(str.begin(),str.end());
            int i=0;
            for(auto&idx: vec){
                s[idx] = str[i];
                i++;
            }
        }
        return s;
    }
};
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