<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(int i ,  multiset<int> &index ,  multiset<char> &val ,string &s ,vector<int> &vis ,vector<int> adj[]) {
    vis[i] = 1 ;
    index.insert(i) ;
    val.insert(s[i]) ;
    for(auto el : adj[i]){
        if(!vis[el]){
            dfs(el ,index,val,s,vis,adj) ;
        }
    }
}
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        string ans = s ;
        vector<int> adj[s.length()] ;
        for(int i=0 ; i<pairs.size() ; i++){
            adj[pairs[i][0]].push_back(pairs[i][1]) ;
            adj[pairs[i][1]].push_back(pairs[i][0]) ;
        }
        vector<int> vis(s.length() ,0) ;
        for(int i=0 ; i<s.length() ; i++){
            multiset<int> index ;
            multiset<char> val ;
            if(!vis[i]){
                dfs(i ,index,val,s,vis,adj) ;
            }
            auto it1 = index.begin();
    auto it2 = val.begin();

    while (it1 != index.end() && it2 != val.end()) {
        ans[*it1] = *it2 ;
        ++it1;
        ++it2;
    }
        }
        return ans ;
    }
};
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