<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 {
public:
    // Check Even
    bool ce(unordered_map<char, int>& v) {
        for (auto& [a, b] : v) {
            if (b % 2 != 0)
                return false;
        }
        return true;
    }
    void updateMap(unordered_map<char, int>& v, string& s, int i, int val) {
        if (s[i] == 'a' || s[i] == 'e' || s[i] == 'i' || s[i] == 'o' ||
            s[i] == 'u') {
            v[s[i]] += val;
        }
    }
    bool check(string& s, unordered_map<char, int> v, int m) {
        int n = s.length();
        bool ans = ce(v);
        if (ans)
            return true;
        for (int i = 0; i + m < n; i++) {
            // remove first
            updateMap(v, s, i, -1);
            // add last
            updateMap(v, s, i + m, 1);
            ans |= ce(v);
            if (ans)
                return true;
        }
        return ans;
    }
    int findTheLongestSubstring(string s) {
        ios::sync_with_stdio(false);
        cin.tie(0);
        cout.tie(0);
        int r = s.length();
        int ans = 0;
        unordered_map<char, int> v;
        // storing all vowels count in map
        for (int i = 0; i < r; i++) {
            updateMap(v, s, i, 1);
        }
        // check all sizes from s.length() -> 0
        for (int i = r; i >= 0; i--) {
            // Adjust window by removing last element
            if (i >= 0 && i < r) {
                updateMap(v, s, i, -1);
            }
            if (check(s, v, i))
                return i;
        }
        return ans;
    }
};
19100