<p>The <strong>variance</strong> of a string is defined as the largest difference between the number of occurrences of <strong>any</strong> <code>2</code> characters present in the string. Note the two characters may or may not be the same.</p>

<p>Given a string <code>s</code> consisting of lowercase English letters only, return <em>the <strong>largest variance</strong> possible among all <strong>substrings</strong> of</em> <code>s</code>.</p>

<p>A <strong>substring</strong> is a contiguous sequence of characters within a string.</p>

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

<pre>
<strong>Input:</strong> s = &quot;aababbb&quot;
<strong>Output:</strong> 3
<strong>Explanation:</strong>
All possible variances along with their respective substrings are listed below:
- Variance 0 for substrings &quot;a&quot;, &quot;aa&quot;, &quot;ab&quot;, &quot;abab&quot;, &quot;aababb&quot;, &quot;ba&quot;, &quot;b&quot;, &quot;bb&quot;, and &quot;bbb&quot;.
- Variance 1 for substrings &quot;aab&quot;, &quot;aba&quot;, &quot;abb&quot;, &quot;aabab&quot;, &quot;ababb&quot;, &quot;aababbb&quot;, and &quot;bab&quot;.
- Variance 2 for substrings &quot;aaba&quot;, &quot;ababbb&quot;, &quot;abbb&quot;, and &quot;babb&quot;.
- Variance 3 for substring &quot;babbb&quot;.
Since the largest possible variance is 3, we return it.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;abcde&quot;
<strong>Output:</strong> 0
<strong>Explanation:</strong>
No letter occurs more than once in s, so the variance of every substring is 0.
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>4</sup></code></li>
	<li><code>s</code> consists of lowercase English letters.</li>
</ul>

class Solution:
    def largestVariance(self, s: str) -> int:
        count_array = [0 for i in range(26)]
        global_max, major_count, minor_count = 0, 0, 0

        for c in s:
            count_array[ord(c) - ord('a')] += 1

        for ind_i, count_i in enumerate(count_array):
            for ind_j, count_j in enumerate(count_array):

                if (ind_i == ind_j or count_i == 0 or count_j == 0):
                    continue
                # Find the max variance of major - minor 
                major = chr(ord('a') + ind_i)
                minor = chr(ord('a') + ind_j)
                major_count = 0
                minor_count = 0

                #The remaining minor in the res of s
                rest_minor = count_j

                for c in s:
                    if c == major:
                        major_count += 1
                    if c == minor:
                        minor_count += 1
                        rest_minor -= 1
                    
                    #only update variance if there is one minor 
                    if minor_count > 0:
                        global_max = max(global_max, major_count - minor_count)
                    
                    #we can discard current substring if there is at least one remaining minor
                    if (major_count < minor_count and rest_minor > 0):
                        major_count = 0
                        minor_count = 0

        return global_max
4927