public void DiameterOfBinaryTreeTest()
{
var s = new Solution();
TreeNode head;
var leftNode = new TreeNode(2, 4, 5);
head = new TreeNode(1, leftNode, new TreeNode(3));
Assert.Equal(3, s.DiameterOfBinaryTree(head));
head = new TreeNode(1);
Assert.Equal(0, s.DiameterOfBinaryTree(head));
head = new TreeNode(1, new TreeNode(2), null);
Assert.Equal(1, s.DiameterOfBinaryTree(head));
head = TreeNode.Build(new int?[] {
4, -7, -3, null, null, -9, -3, 9, -7, -4, null, 6, null, -6, -6, null,
null, 0, 6, 5, null, 9, null, null, -1, -4, null, null, null, -2
});
Assert.Equal(8, s.DiameterOfBinaryTree(head));
}