Count of Substrings Containing Every Vowel and K Consonants II
<p>You are given a string <code>word</code> and a <strong>non-negative</strong> integer <code>k</code>.</p>

<p>Return the total number of <span data-keyword="substring-nonempty">substrings</span> of <code>word</code> that contain every vowel (<code>&#39;a&#39;</code>, <code>&#39;e&#39;</code>, <code>&#39;i&#39;</code>, <code>&#39;o&#39;</code>, and <code>&#39;u&#39;</code>) <strong>at least</strong> once and <strong>exactly</strong> <code>k</code> consonants.</p>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">word = &quot;aeioqq&quot;, k = 1</span></p>

<p><strong>Output:</strong> <span class="example-io">0</span></p>

<p><strong>Explanation:</strong></p>

<p>There is no substring with every vowel.</p>
</div>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">word = &quot;aeiou&quot;, k = 0</span></p>

<p><strong>Output:</strong> <span class="example-io">1</span></p>

<p><strong>Explanation:</strong></p>

<p>The only substring with every vowel and zero consonants is <code>word[0..4]</code>, which is <code>&quot;aeiou&quot;</code>.</p>
</div>

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

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">word = &quot;</span>ieaouqqieaouqq<span class="example-io">&quot;, k = 1</span></p>

<p><strong>Output:</strong> 3</p>

<p><strong>Explanation:</strong></p>

<p>The substrings with every vowel and one consonant are:</p>

<ul>
	<li><code>word[0..5]</code>, which is <code>&quot;ieaouq&quot;</code>.</li>
	<li><code>word[6..11]</code>, which is <code>&quot;qieaou&quot;</code>.</li>
	<li><code>word[7..12]</code>, which is <code>&quot;ieaouq&quot;</code>.</li>
</ul>
</div>

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

<ul>
	<li><code>5 &lt;= word.length &lt;= 2 * 10<sup>5</sup></code></li>
	<li><code>word</code> consists only of lowercase English letters.</li>
	<li><code>0 &lt;= k &lt;= word.length - 5</code></li>
</ul>
Hash Table; String; Sliding Window
class Solution {
    public long countOfSubstrings(String word, int k) {
        return f(word, k) - f(word, k + 1);
    }

    private long f(String word, int k) {
        long ans = 0;
        int l = 0, x = 0;
        Map<Character, Integer> cnt = new HashMap<>(5);
        for (char c : word.toCharArray()) {
            if (vowel(c)) {
                cnt.merge(c, 1, Integer::sum);
            } else {
                ++x;
            }
            while (x >= k && cnt.size() == 5) {
                char d = word.charAt(l++);
                if (vowel(d)) {
                    if (cnt.merge(d, -1, Integer::sum) == 0) {
                        cnt.remove(d);
                    }
                } else {
                    --x;
                }
            }
            ans += l;
        }
        return ans;
    }

    private boolean vowel(char c) {
        return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
    }
}
