Maximum Product of Two Elements in an Array
Given the array of integers <code>nums</code>, you will choose two different indices <code>i</code> and <code>j</code> of that array. <em>Return the maximum value of</em> <code>(nums[i]-1)\*(nums[j]-1)</code>.

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

<pre>
<strong>Input:</strong> nums = [3,4,5,2]
<strong>Output:</strong> 12 
<strong>Explanation:</strong> If you choose the indices i=1 and j=2 (indexed from 0), you will get the maximum value, that is, (nums[1]-1)*(nums[2]-1) = (4-1)*(5-1) = 3*4 = 12. 
</pre>

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

<pre>
<strong>Input:</strong> nums = [1,5,4,5]
<strong>Output:</strong> 16
<strong>Explanation:</strong> Choosing the indices i=1 and j=3 (indexed from 0), you will get the maximum value of (5-1)*(5-1) = 16.
</pre>

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

<pre>
<strong>Input:</strong> nums = [3,7]
<strong>Output:</strong> 12
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<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>2 &lt;= nums.length &lt;= 500</code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10^3</code></li>
</ul>
Array; Sorting; Heap (Priority Queue)
int maxProduct(int* nums, int numsSize) {
    int max = 0;
    int submax = 0;
    for (int i = 0; i < numsSize; i++) {
        int num = nums[i];
        if (num > max) {
            submax = max;
            max = num;
        } else if (num > submax) {
            submax = num;
        }
    }
    return (max - 1) * (submax - 1);
}