<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 Disjoint
{
public:
    vector<int> parent,size;
    Disjoint(int n)
    {
        parent.resize(n,0);
        for(int i=0;i<n;i++)
            parent[i]=i;
        size.resize(n,1);

    }

    int findpar(int u)
    {
        if(parent[u]==u)
            return u;
        else
        {
            return parent[u]=findpar(parent[u]);
        }
    }

    void unionsize(int u,int v)
    {
        int upar=findpar(u);int vpar=findpar(v);
        if(upar==vpar)
            return;
        else
        {
            if(size[upar]>size[vpar])
            {
                parent[vpar]=upar;
                size[upar]+=size[vpar];
            }
            else
            {
                parent[upar]=vpar;
                size[vpar]+=size[upar];
            }
           
        }
    }
};
class Solution {
public:
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
        int n=s.size();
        Disjoint ds(n);
        for(int i=0;i<pairs.size();i++)
        {
            ds.unionsize(pairs[i][0],pairs[i][1]);

        }

        map<int,vector<int>> mp;
        for(int i=0;i<n;i++)
        {
            int par=ds.findpar(i);
            mp[par].push_back(i);
        }
        string res(n,'*');
        for(auto it:mp)
        {
            vector<int> cur=it.second;
            string temp="";
            for(int c:cur)
            {
                temp+=s[c];
            }
            sort(temp.begin(),temp.end());
            
            for(int i=0;i<cur.size();i++)
            {
                res[cur[i]]=temp[i];
            }
        }
        return res;
    }
};
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