<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;
    vector<int>size;
    DisJoint(int n)
    {
        parent.resize(n,0);
        size.resize(n,0);
        for(int i=0;i<n;i++)
        {
            parent[i]=i;
        }
    }
    int findParent(int node)
    {
        if(node==parent[node])
        return node;
        return parent[node]=findParent(parent[node]);
    }
    void bySize(int u,int v)
    {
        int ulu=findParent(u);
        int ulv=findParent(v);
        if(size[ulu]>size[ulv])
        {
            parent[ulv]=ulu;
            size[ulu]+=size[ulv];
        }
        else
        {
            parent[ulu]=ulv;
            size[ulv]+=size[ulu];
        }
    }
};
class Solution {
public:
    string smallestStringWithSwaps(string s, vector<vector<int>>& pairs) {
  int n=s.length();
  DisJoint ds(n);
  for(int i=0;i<pairs.size();i++)
  {
    ds.bySize(pairs[i][0],pairs[i][1]);
  }      
  vector<vector<int>>mp(s.length());
  for(int i=0;i<n;i++)
  {
    mp[ds.findParent(i)].push_back(i);
  }
  for(auto it:mp)
  {
    string ss="";
    for(auto ids:it)
    {
        ss+=s[ids];
    }
    sort(ss.begin(),ss.end());
    for(int i=0;i<it.size();i++)
    {
        s[it[i]]=ss[i];
    }
  }
  return s;
  
    }
};
54762