<p>A <strong>valid IP address</strong> consists of exactly four integers separated by single dots. Each integer is between <code>0</code> and <code>255</code> (<strong>inclusive</strong>) and cannot have leading zeros.</p>

<ul>
	<li>For example, <code>&quot;0.1.2.201&quot;</code> and <code>&quot;192.168.1.1&quot;</code> are <strong>valid</strong> IP addresses, but <code>&quot;0.011.255.245&quot;</code>, <code>&quot;192.168.1.312&quot;</code> and <code>&quot;192.168@1.1&quot;</code> are <strong>invalid</strong> IP addresses.</li>
</ul>

<p>Given a string <code>s</code> containing only digits, return <em>all possible valid IP addresses that can be formed by inserting dots into </em><code>s</code>. You are <strong>not</strong> allowed to reorder or remove any digits in <code>s</code>. You may return the valid IP addresses in <strong>any</strong> order.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;25525511135&quot;
<strong>Output:</strong> [&quot;255.255.11.135&quot;,&quot;255.255.111.35&quot;]
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;0000&quot;
<strong>Output:</strong> [&quot;0.0.0.0&quot;]
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;101023&quot;
<strong>Output:</strong> [&quot;1.0.10.23&quot;,&quot;1.0.102.3&quot;,&quot;10.1.0.23&quot;,&quot;10.10.2.3&quot;,&quot;101.0.2.3&quot;]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= s.length &lt;= 20</code></li>
	<li><code>s</code> consists of digits only.</li>
</ul>

class Solution {
public:
 bool validIpAddress(string a){
     int x= stoi(a);
     if(x>0&&x<=255){
        if(a[0]!='0'){
            return true;
        }
        return false;
     }
     if(x==0&&a.length()==1){ 
      return true;
     }
     return false;
 }
    vector<string> restoreIpAddresses(string s) {
        vector<string>list;
        string sample="";
        ipAddress(list,sample,0,0,s);
        return list;
    }
    void ipAddress(vector<string>&list,string sample,int index,int dot_count,string s){
      if(dot_count==4&&index==s.length()){
  sample.pop_back();
    list.push_back(sample);
    return;
  }
   string temp="";
   for(int i=index;i<s.length();i++){
    temp+=s[i];
    if(validIpAddress(temp)==true){
        ipAddress(list,sample+temp+'.',i+1,dot_count+1,s);
    }
    else{
        break;
    }
   } 
    }
};
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