public void Test(string inputStr, string expected)
{
var output = RecoverFromPreorder(inputStr);
var outputStr = BinaryTreeConvert.Serialize(output);
outputStr.Should().Be(expected);
}
public void Test(string inputStr, int key, string expected)
{
var root = BinaryTreeConvert.Deserialize(inputStr);
var s = new Solution();
var output = s.DeleteNode(root, key);
var outputStr = BinaryTreeConvert.Serialize(output);
outputStr.Should().Be(expected);
}