Recursively generates a random tree with the specified max depth and sibling count.

RandomTreeGenerator.cs

private static void PopulateNodeWithRandomSubtree(TreeNode nodeToPopulate, int currentLevel)
{
    // These can be the arguments of the function if necessary.
    const int maxTreeDepth = 5;
    const int maxSiblingCount = 4;

    // Generate children for this node if a fair coin toss yields 0 at least QUOTA times,
    // where QUOTA increases after each level. That way the deeper it gets, the less will
    // be the probability of generating more children.

    var quota = currentLevel * currentLevel * 1.0 / maxTreeDepth;
    var actual = Enumerable.Range(1, currentLevel)
        .Select(i => randomGenerator.Next(0, 2))
        .Count(i => i == 0);

    bool shouldGenerateChildren = actual >= quota;
    if (shouldGenerateChildren)
    {
        var nodeCount = randomGenerator.Next(1, maxSiblingCount + 1);
        for (int i = 0; i < nodeCount; i++)
        {
            var newChild = new TreeNode { Value = GetRandomValue() };
            nodeToPopulate.Nodes.Add(newChild);
            PopulateNodeWithRandomSubtree(newChild, currentLevel + 1);
        }
    }
}


/*
    How to use:

    var root = new TreeNode { Value = GetRandomValue() };
    PopulateNodeWithRandomSubtree(root, 1);
*/