<p>You are given the string <code>croakOfFrogs</code>, which represents a combination of the string <code>&quot;croak&quot;</code> from different frogs, that is, multiple frogs can croak at the same time, so multiple <code>&quot;croak&quot;</code> are mixed.</p>

<p><em>Return the minimum number of </em>different<em> frogs to finish all the croaks in the given string.</em></p>

<p>A valid <code>&quot;croak&quot;</code> means a frog is printing five letters <code>&#39;c&#39;</code>, <code>&#39;r&#39;</code>, <code>&#39;o&#39;</code>, <code>&#39;a&#39;</code>, and <code>&#39;k&#39;</code> <strong>sequentially</strong>. The frogs have to print all five letters to finish a croak. If the given string is not a combination of a valid <code>&quot;croak&quot;</code> return <code>-1</code>.</p>

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

<pre>
<strong>Input:</strong> croakOfFrogs = &quot;croakcroak&quot;
<strong>Output:</strong> 1 
<strong>Explanation:</strong> One frog yelling &quot;croak<strong>&quot;</strong> twice.
</pre>

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

<pre>
<strong>Input:</strong> croakOfFrogs = &quot;crcoakroak&quot;
<strong>Output:</strong> 2 
<strong>Explanation:</strong> The minimum number of frogs is two. 
The first frog could yell &quot;<strong>cr</strong>c<strong>oak</strong>roak&quot;.
The second frog could yell later &quot;cr<strong>c</strong>oak<strong>roak</strong>&quot;.
</pre>

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

<pre>
<strong>Input:</strong> croakOfFrogs = &quot;croakcrook&quot;
<strong>Output:</strong> -1
<strong>Explanation:</strong> The given string is an invalid combination of &quot;croak<strong>&quot;</strong> from different frogs.
</pre>

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

<ul>
	<li><code>1 &lt;= croakOfFrogs.length &lt;= 10<sup>5</sup></code></li>
	<li><code>croakOfFrogs</code> is either <code>&#39;c&#39;</code>, <code>&#39;r&#39;</code>, <code>&#39;o&#39;</code>, <code>&#39;a&#39;</code>, or <code>&#39;k&#39;</code>.</li>
</ul>

class Solution {
public:
    int minNumberOfFrogs(string croakOfFrogs) {
        unordered_map<char, int> qmap;
        for (int i = 0; i < croakOfFrogs.size(); i++) {
            qmap[croakOfFrogs[i]]++;
            if (qmap['r'] > qmap['c'] or qmap['o'] > qmap['c'] or
                qmap['a'] > qmap['c'] or qmap['k'] > qmap['c'] or
                qmap['r'] < qmap['o'] or qmap['r'] < qmap['a'] or
                qmap['r'] < qmap['k'] or qmap['o'] < qmap['a'] or
                qmap['o'] < qmap['k'] or qmap['a'] < qmap['k'])
                return -1;
        }
        int x = qmap[croakOfFrogs[0]];
        for (auto it : qmap) {
            if (qmap[it.first] != x)
                return -1;
        }
        int val = 0;
        int ans = 0;
        for (int i = 0; i < croakOfFrogs.size(); i++) {
            if (croakOfFrogs[i] == 'c')
                val++;
            else if (croakOfFrogs[i] == 'k')
                val--;
            ans = max(val, ans);
        }
        return ans;
    }
};
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