<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(int pos, vector<int>adj[], vector<int>&vis,vector<int>&group, int top){
        vis[pos]=1;
        group[pos]=top;
        for(auto it: adj[pos]){
            if(vis[it]==0)dfs(it,adj,vis,group,top);
        }
    }
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        if(pairs.size()==0)return s;
        int n= s.size();
        vector<int>adj[n];
        for(auto &it:pairs){
            adj[it[0]].push_back(it[1]);
            adj[it[1]].push_back(it[0]);
        }
        vector<int>vis(n,0);
        vector<int>group(n);
        for(int i=0;i<n;i++){
            group[i]=i;
        }
        for(int i=0;i<n;i++){
            if(vis[i]==0)dfs(i,adj,vis,group,i);
        }
        for(int i=0;i<n;i++){
            cout<<group[i]<<" ";
        }
        cout<<endl;
        // return "Yes";
        unordered_map<int,vector<int>>mp;
        for(int i=0;i<n;i++){
            mp[group[i]].push_back(i);
        }
        // int maxi=INT_MIN;
        // for(int i=0;i<mp.size();i++){
        //     int size=mp[i].size();
        //     maxi= max(maxi,size);
        // }
        for(int i=0;i<mp.size();i++){
            // if(mp[i].size()==maxi){
                string temp="";
                for(int j=0;j<mp[i].size();j++){
                    temp+=s[mp[i][j]];
                }
                sort(temp.begin(),temp.end());
                for(int j=0;j<mp[i].size();j++){
                    s[mp[i][j]]=temp[j];
                }

            // }
        }
       return s;
    }
};
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