Min Loss, by HackerRank

Problem statement is here: https://www.hackerrank.com/challenges/minimum-loss. At first I thought about an N^2 solution, but with N ~= 10^5, such approach would definitely time out. I read some of the discussions (no shame, really, purpose of hacker-rank practice is for one to learn) and an idea was brought up there:

•  Build a Binary Search Tree out of the numbers
•  As you add a new number, while going down the tree keep track of the min-loss

Assuming that the tree is going to be relatively balanced (and that's a fair assumption given the statement that the input numbers are all unique), the execution time becomes near NLogN, which works quick enough for N ~= 10^5. Code is below, and a picture of me and the team who's bringing Bots to Search Engines!!! :) Many cheers, Marcelo.

using System;
using System.Collections.Generic;
using System.IO;
class Solution
{
    static void Main(String[] args)
    {
        int n = Int32.Parse(Console.ReadLine());
        long minLoss = Int64.MaxValue;
        string[] parts = Console.ReadLine().Split(' ');

        BST bst = new BST(Int64.Parse(parts[0]));
        for (int i = 1; i < n; i++)
        {
            bst.Add(Int64.Parse(parts[i]), ref minLoss);
        }
        Console.WriteLine(minLoss);
    }
}

class BST
{
    private long number;
    private BST left;
    private BST right;

    private BST() { }

    public BST(long number)
    {
        this.number = number;
        this.left = null;
        this.right = null;
    }

    public void Add(long number,
                    ref long minLoss)
    {
        if (number >= this.number)
        {
            if (this.right == null)
            {
                this.right = new BST(number);
            }
            else
            {
                this.right.Add(number, ref minLoss);
            }
        }
        else
        {
            if (this.number - number < minLoss) minLoss = this.number - number;
            if (this.left == null)
            {
                this.left = new BST(number);
            }
            else
            {
                this.left.Add(number, ref minLoss);
            }
        }
    }
}