public void NormalCases()
{
var t = TreeFromPreorderInorder.BuildTree(new[] { 1, 2, 4, 5, 3, 6 }, new[] { 4, 2, 5, 1, 6, 3 });
Assert.AreEqual(1, t.val);
Assert.AreEqual(2, t.left.val);
Assert.AreEqual(3, t.right.val);
Assert.AreEqual(4, t.left.left.val);
Assert.AreEqual(5, t.left.right.val);
Assert.AreEqual(6, t.right.left.val);
}
public void CornerCases()
{
Assert.AreEqual(null, TreeFromPreorderInorder.BuildTree(null, null));
Assert.AreEqual(null, TreeFromPreorderInorder.BuildTree(new int[0], new int[0]));
Assert.AreEqual(new TreeFromPreorderInorder.TreeNode(5).val, TreeFromPreorderInorder.BuildTree(new int[] { 5 }, new int[] { 5 }).val);
}