<p>A string <code>s</code> is called <strong>happy</strong> if it satisfies the following conditions:</p>

<ul>
	<li><code>s</code> only contains the letters <code>&#39;a&#39;</code>, <code>&#39;b&#39;</code>, and <code>&#39;c&#39;</code>.</li>
	<li><code>s</code> does not contain any of <code>&quot;aaa&quot;</code>, <code>&quot;bbb&quot;</code>, or <code>&quot;ccc&quot;</code> as a substring.</li>
	<li><code>s</code> contains <strong>at most</strong> <code>a</code> occurrences of the letter <code>&#39;a&#39;</code>.</li>
	<li><code>s</code> contains <strong>at most</strong> <code>b</code> occurrences of the letter <code>&#39;b&#39;</code>.</li>
	<li><code>s</code> contains <strong>at most</strong> <code>c</code> occurrences of the letter <code>&#39;c&#39;</code>.</li>
</ul>

<p>Given three integers <code>a</code>, <code>b</code>, and <code>c</code>, return <em>the <strong>longest possible happy </strong>string</em>. If there are multiple longest happy strings, return <em>any of them</em>. If there is no such string, return <em>the empty string </em><code>&quot;&quot;</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> a = 1, b = 1, c = 7
<strong>Output:</strong> &quot;ccaccbcc&quot;
<strong>Explanation:</strong> &quot;ccbccacc&quot; would also be a correct answer.
</pre>

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

<pre>
<strong>Input:</strong> a = 7, b = 1, c = 0
<strong>Output:</strong> &quot;aabaa&quot;
<strong>Explanation:</strong> It is the only correct answer in this case.
</pre>

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

<ul>
	<li><code>0 &lt;= a, b, c &lt;= 100</code></li>
	<li><code>a + b + c &gt; 0</code></li>
</ul>

class Solution {
public:
    string longestDiverseString(int a, int b, int c) {
        priority_queue<pair<int,char>>pq;
        if (a!=0) pq.push({a,'a'});
        if (b!=0) pq.push({b,'b'});
        if (c!=0) pq.push({c,'c'});
    
        string ret = "";
        while(!pq.empty()){

            if(pq.size() == 1){
                auto x = pq.top(); pq.pop();
                int k = min(2, x.first);
                for(int i = 0 ; i < k ; i++) ret += x.second;
                return ret;
            }

            auto x = pq.top(); pq.pop(); // 取出第1多的element
            auto y = pq.top(); pq.pop(); // 取出第2多的element

            int k = min(2,1 + x.first - y.first);
            for(int i = 0 ; i < k ; i++) ret += x.second;
            ret += y.second;

            x.first -= k;
            y.first -= 1;
            if(x.first != 0) pq.push(x);
            if(y.first != 0) pq.push(y);
        }
        return ret;
    }
};
// 5  5  a b
// 4  4  a b a b


// 5  4  a a b
// 3  3
7800