<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>

#include <vector>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <queue>

using namespace std;

class Solution {
public:
    void dfs(int node, unordered_map<int, vector<int>>& graph, vector<int>& visited, vector<int>& component) {
        visited[node] = 1;
        component.push_back(node);
        for (int neighbor : graph[node]) {
            if (!visited[neighbor]) {
                dfs(neighbor, graph, visited, component);
            }
        }
    }

    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        unordered_map<int, vector<int>> graph;
        for (const vector<int>& pair : pairs) {
            graph[pair[0]].push_back(pair[1]);
            graph[pair[1]].push_back(pair[0]);
        }
        vector<int> visited(s.size(), 0);
        vector<vector<int>> components;
        for (int i = 0; i < s.size(); i++) {
            if (!visited[i]) {
                vector<int> component;
                dfs(i, graph, visited, component);
                components.push_back(component);
            }
        }
        string result = s;
        for (const vector<int>& component : components) {
            vector<int> indices = component;
            vector<char> chars;
            for (int index : indices) {
                chars.push_back(s[index]);
            }
            sort(indices.begin(), indices.end());
            sort(chars.begin(), chars.end());

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

82062