<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:
        # Initialize the index of the "largest" character found
        max_char_idx = 0
        # Search for the maximum character in the string
        max_char = max(s)
        
        # Collect indices of all occurrences of the maximum character
        candidates = [i for i, char in enumerate(s) if char == max_char]
        
        # Find the largest lexicographical substring starting at each candidate index
        max_substr = ''
        for start in candidates:
            # Generate substring from current candidate index to the end of the string
            substr = s[start:]
            # Compare with the current maximum substring and update if larger
            if substr > max_substr:
                max_substr = substr
        
        return max_substr

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