<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 node,vector<char>&chars,vector<int>&indices,vector<int>adjList[],vector<int>& vis,string &s){
    vis[node]=1;
    chars.push_back(s[node]);
    indices.push_back(node);

    for(auto it:adjList[node]){
        if(!vis[it]){
            dfs(it,chars,indices,adjList,vis,s);
        }
    }
}
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        int n=s.size();
        vector<int>adjList[n];

        for(auto it:pairs){
            int u=it[0];
            int v=it[1];
            adjList[u].push_back(v);
            adjList[v].push_back(u);
        }

        vector<int>vis(n);
        string ans="";
        for(int i=0;i<n;i++)ans+=" ";

        for(int i=0;i<n;i++){
            if(!vis[i]){
                vector<int>indices;
                vector<char>chars;
                dfs(i,chars,indices,adjList,vis,s);
                sort(indices.begin(),indices.end());
                sort(chars.begin(),chars.end());

                for(int i=0;i<indices.size();i++)ans[indices[i]]=chars[i];
            }
        }

        return ans;
    }
};
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