<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<vector<int> > &graph, vector<bool> &visited, vector<int> &members, int i){
        visited[i] = true;
        members.push_back(i);

        for( auto nbr : graph[i] ){
            if( !visited[nbr] ){
                dfs(graph, visited, members, nbr);
            }
        }

        return;
    }

    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        int n = s.size();
        vector<vector<int> > graph(n);

        for( int i = 0; i < pairs.size(); i++){
            graph[pairs[i][1]].push_back(pairs[i][0]);
            graph[pairs[i][0]].push_back(pairs[i][1]);
        }

        vector<vector<int> > connectedIndices; 
        vector<bool> visited(n, false);
        for( int i = 0; i < n; i++ ){
            if( visited[i] == false){
                vector<int> members;
                dfs(graph, visited, members, i);
                connectedIndices.push_back(members);
            }
        }

        for( int i = 0; i < connectedIndices.size(); i++){
            string temp = "";
            for( int j = 0; j < connectedIndices[i].size(); j++){
                temp+=s[connectedIndices[i][j]];
            }
            
            sort(temp.begin(), temp.end());
            sort(connectedIndices[i].begin(), connectedIndices[i].end());

            for( int j = 0; j < connectedIndices[i].size(); j++){
                s[connectedIndices[i][j]] = temp[j];
            }
        }

        return s;

    }
};
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