<p>You are given an <code>m x n</code> integer matrix <code>grid</code>.</p>
<p>A <strong>rhombus sum</strong> is the sum of the elements that form <strong>the</strong><strong>border</strong> of a regular rhombus shape in <code>grid</code>. The rhombus must have the shape of a square rotated 45 degrees with each of the corners centered in a grid cell. Below is an image of four valid rhombus shapes with the corresponding colored cells that should be included in each <strong>rhombus sum</strong>:</p>
<p>Note that the rhombus can have an area of 0, which is depicted by the purple rhombus in the bottom right corner.</p>
<p>Return <em>the biggest three <strong>distinct rhombus sums</strong> in the </em><code>grid</code><em> in <strong>descending order</strong></em><em>. If there are less than three distinct values, return all of them</em>.</p>