<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:
void fun(int i,int c,string& s,string& temp,vector<string>&ans)
{
    if(c==4 && i==s.size())
    {
    temp.pop_back();
    ans.push_back(temp);
    temp.push_back('.');
    return;
    }
    if((c==4 && i<s.size()) || i==s.size())
    return;
    temp.push_back(s[i]);
    temp.push_back('.');
    fun(i+1,c+1,s,temp,ans);
    temp.pop_back();
    temp.pop_back();
    if(i<s.size()-1 && s[i]!='0')
    {
    temp.push_back(s[i]);
    temp.push_back(s[i+1]);
    temp.push_back('.');
    fun(i+2,c+1,s,temp,ans);
    temp.pop_back();
    temp.pop_back();
    temp.pop_back();
    }
    if(i<s.size()-2 &&( (s[i]=='2' && s[i+1]<='4') || s[i]=='1' || (s[i]<='2' && s[i+1]=='5' && s[i+2]<='5')) && s[i]!='0')
    {
    temp.push_back(s[i]);
    temp.push_back(s[i+1]);
    temp.push_back(s[i+2]);
    temp.push_back('.');
    fun(i+3,c+1,s,temp,ans);
    temp.pop_back();
    temp.pop_back();
    temp.pop_back(); 
    temp.pop_back(); 
    }
}
    vector<string> restoreIpAddresses(string s) {
        vector<string>ans;
        string temp="";
        fun(0,0,s,temp,ans);
        return ans;
    }
};
8521