<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:
      unordered_map<int, vector<int>> adj;
    string str;

    void dfs(int node, vector<int>& vis, vector<int>& indices, vector<char>& chars) {
        vis[node] = 1;
        indices.push_back(node);
        chars.push_back(str[node]);

        for (auto it : adj[node]) {
            if (!vis[it]) {
                dfs(it, vis, indices, chars);
            }
        }
    }

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

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

        vector<int> vis(n, 0);

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

        return s;
    }
};
83637