<p>Given a string <code>s</code>, return <em>the last substring of</em> <code>s</code> <em>in lexicographical order</em>.</p>

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

<pre>
<strong>Input:</strong> s = &quot;abab&quot;
<strong>Output:</strong> &quot;bab&quot;
<strong>Explanation:</strong> The substrings are [&quot;a&quot;, &quot;ab&quot;, &quot;aba&quot;, &quot;abab&quot;, &quot;b&quot;, &quot;ba&quot;, &quot;bab&quot;]. The lexicographically maximum substring is &quot;bab&quot;.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;leetcode&quot;
<strong>Output:</strong> &quot;tcode&quot;
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 4 * 10<sup>5</sup></code></li>
	<li><code>s</code> contains only lowercase English letters.</li>
</ul>

class Solution {
public:
    string lastSubstring(string s) {
        int n =s.length();
        int max_ind=n-1;
        int i=n-2;
        while(i>=0)
        {
            if(s[i]>s[max_ind])
                max_ind=i;
            else if(s[i]==s[max_ind])
            {
                int j=1;
                while((max_ind+j)<n && s[i+j]==s[max_ind+j] && (i+j)!=max_ind) j++;
                
                if(s[i+j]>=s[max_ind+j] || (max_ind+j)>=n)
                    max_ind=i;
            }
            i--;
        }
        return s.substr(max_ind);
    }
};
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