<p>A tree is an undirected graph in which any two vertices are connected by <i>exactly</i> one path. In other words, any connected graph without simple cycles is a tree.</p>
<p>Given a tree of <code>n</code> nodes labelled from <code>0</code> to <code>n - 1</code>, and an array of <code>n - 1</code> <code>edges</code> where <code>edges[i] = [a<sub>i</sub>, b<sub>i</sub>]</code> indicates that there is an undirected edge between the two nodes <code>a<sub>i</sub></code> and <code>b<sub>i</sub></code> in the tree, you can choose any node of the tree as the root. When you select a node <code>x</code> as the root, the result tree has height <code>h</code>. Among all possible rooted trees, those with minimum height (i.e. <code>min(h)</code>) are called <strong>minimum height trees</strong> (MHTs).</p>
<p>Return <em>a list of all <strong>MHTs'</strong> root labels</em>. You can return the answer in <strong>any order</strong>.</p>
<p>The <strong>height</strong> of a rooted tree is the number of edges on the longest downward path between the root and a leaf.</p>
