<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 dfs(vector<int> &ind, vector<char> &letter,vector<int> adj[], int i, vector<int> &vis, string &s){
        vis[i] = 1;
        ind.push_back(i);
        letter.push_back(s[i]);

        for(auto it: adj[i])
        {
            if(!vis[it]){
                dfs(ind,letter,adj,it,vis,s);
            }
        }
    }

    string smallestStringWithSwaps(string s, vector<vector<int>>& arr) {
        int n  = s.size();
        vector<int> adj[n];
        vector<int> vis(n,0);
        for(auto it: arr){
            adj[it[0]].push_back(it[1]);
            adj[it[1]].push_back(it[0]);
        }

        for(int i = 0;i<arr.size();i++){
            vector<int> ind;
            vector<char> letter ;

            if(!vis[i]){
                dfs(ind,letter,adj,i,vis,s);
            }

            sort(ind.begin(),ind.end());
            sort(letter.begin(),letter.end());

            for(int i = 0;i<ind.size();i++){
                s[ind[i]] = letter[i];
            }
        }

        return s;
    }
};
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