<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 start, vector<vector<int>> &adj, vector<int> &visited, int count)
    {
        if(visited[start] != 0)
            return;
        visited[start] = count;
        for(auto x: adj[start])
        {
            if(visited[x] == 0)
                dfs(x, adj, visited, count);
        }
        return;
    }
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        vector<vector<int>> adj(s.length());
        for(auto p:pairs)
        {
            adj[p[0]].push_back(p[1]);
            adj[p[1]].push_back(p[0]);
        }
        vector<int> visited(s.length(), 0);
        int count = 1;
        for(int i = 0; i<s.length(); i++)
        {
            if(visited[i] != 0)
                continue;
            dfs(i, adj, visited, count);
            count++;
        }
        count--;
        // cout<<count<<endl;
        vector<string> temps(count, "");
        for(int i = 0;i<s.length(); i++)
        {
            temps[visited[i]-1] += s[i];
        }
        for(int i = 1; i<=count; i++)
        {
            sort(temps[i-1].begin(), temps[i-1].end());
            // cout<<temps[i-1]<<endl;
        }
        
        vector<int> indices(count, 0);
        string res = "";
        for(int i = 0; i<s.length(); i++)
        {
            res += temps[visited[i]-1][indices[visited[i]-1]];
            indices[visited[i]-1]++;
        }
        return res;
    }
};
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