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

        vector<vector<int>> adj(n);

        for(auto x : pairs){
            adj[x[0]].push_back(x[1]);
            adj[x[1]].push_back(x[0]);
        }

        map<int, vector<char>> comp;
        map<int, vector<int>> idx;
        vector<bool> vis(n);

        int color = 0;

        function<void(int)> dfs = [&](int node){
            vis[node] = true;
            
            comp[color].push_back(s[node]);
            idx[color].push_back(node);

            for(int neighbor : adj[node]){
                if(!vis[neighbor]) dfs(neighbor);
            }
        };

        for(int i = 0; i < n; i++){
            if(!vis[i]) dfs(i), color++;
        }

        vector<char> ans(n);


        for(int i = 0; i < color; i++){
            sort(idx[i].begin(), idx[i].end());
            sort(comp[i].begin(), comp[i].end());
            for(int j = 0; j < comp[i].size(); j++){
                ans[idx[i][j]] = comp[i][j];
            }
        }

        string finalAns = "";

        for(char c : ans){
            finalAns += c;
        }

        return finalAns;

    } 
};
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