<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:
    def lastSubstring(self, s: str) -> str:
 
        maxchar = 'a'
        index = []
    
        # We store all the indexes 
        # of maximum characters we 
        # have in the string
        for i in range(len(s)):
            if (s[i] == maxchar):
                index.append(i)
            elif s[i]> maxchar:
                maxchar= s[i]
                index=[i]
    
        maxstring = ""
    
        # We form a substring from that 
        # maximum character index till 
        # end and check if its greater
        # that maxstring
        for i in range(len(index)):
            if (s[index[i]: len(s)] > 
                maxstring):
                maxstring = s[index[i]: 
                            len(s)]
        return maxstring
            
        
6689