<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(string &s,vector<vector<int>> &adj,vector<bool> &vis,int sv,priority_queue<int, vector<int>, greater<int>> &pq1,priority_queue<char, vector<char>, greater<char>> &pq2 ){
        vis[sv]=true;
        pq1.push(sv);
        pq2.push(s[sv]);
        for(auto it:adj[sv]){
            if(!vis[it]){
                dfs(s,adj,vis,it,pq1,pq2);
            }
        }
    }


    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        int n = s.length();
        vector<vector<int>> adj(n);
        for (auto it : pairs) {
            adj[it[0]].push_back(it[1]);
            adj[it[1]].push_back(it[0]);
        }
        string ans(s);
        vector<bool> vis(n, false);
        for (int i = 0; i < n; i++) {
            if (!vis[i]) {
                priority_queue<char, vector<char>, greater<char>> pq2;
                priority_queue<int, vector<int>, greater<int>> pq1;
                dfs(s,adj,vis,i,pq1,pq2);
                while(!pq1.empty()){
                    ans[pq1.top()]=pq2.top();
                    pq1.pop();
                    pq2.pop();
                }
            }
        }
        return ans;
    }
};
77862