<p>Given the string <code>s</code>, return the size of the longest substring containing each vowel an even number of times. That is, &#39;a&#39;, &#39;e&#39;, &#39;i&#39;, &#39;o&#39;, and &#39;u&#39; must appear an even number of times.</p>

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

<pre>
<strong>Input:</strong> s = &quot;eleetminicoworoep&quot;
<strong>Output:</strong> 13
<strong>Explanation: </strong>The longest substring is &quot;leetminicowor&quot; which contains two each of the vowels: <strong>e</strong>, <strong>i</strong> and <strong>o</strong> and zero of the vowels: <strong>a</strong> and <strong>u</strong>.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;leetcodeisgreat&quot;
<strong>Output:</strong> 5
<strong>Explanation:</strong> The longest substring is &quot;leetc&quot; which contains two e&#39;s.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;bcbcbc&quot;
<strong>Output:</strong> 6
<strong>Explanation:</strong> In this case, the given string &quot;bcbcbc&quot; is the longest because all vowels: <strong>a</strong>, <strong>e</strong>, <strong>i</strong>, <strong>o</strong> and <strong>u</strong> appear zero times.
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 5 x 10^5</code></li>
	<li><code>s</code>&nbsp;contains only lowercase English letters.</li>
</ul>

class Solution:
    def findTheLongestSubstring(self, s: str) -> int:
        return brute_force_fls(s)


def brute_force_fls(input_string):
    counts_before = [{l: 0 for l in "aeiou"}]
    for letter in input_string:
        new_counts = {k:v for k, v in counts_before[-1].items()}
        if letter in new_counts:
            new_counts[letter] += 1
        counts_before.append(new_counts)
    # print(counts_before)

    def is_valid_solution(s, t):
        for letter in "aeiou":
            if (counts_before[t][letter] - counts_before[s][letter]) % 2 == 1:
                return False
        return True

    n = len(input_string)
    for l in range(n, -1, -1):
        for s in range(0, n-l+1):
            if s > 0  and input_string[s-1] not in "aeiou":
                continue

            t = s + l
            if t < n and input_string[t] not in "aeiou":
                continue

            if is_valid_solution(s, t):
                print(s, t)
                return l


        
664