/// <summary>
/// Returns an item chosen randomly by weight (higher weights are more likely),
/// and replaces it so that it can be chosen again
/// </summary>
public TKey NextWithReplacement()
{
VerifyHaveItemsToChooseFrom();
Node currentNode = _root;
long randomNumber = _random.NextLong(0, TotalWeight) + 1; //[1, TotalWeight] inclusive
while (true)
{
if (currentNode.left.subtreeWeight >= randomNumber)
{
currentNode = currentNode.left;
}
else
{
randomNumber -= currentNode.left.subtreeWeight;
if (currentNode.right.subtreeWeight >= randomNumber)
{
currentNode = currentNode.right;
}
else
{
return(currentNode.key);
}
}
}
}
/// <summary>
/// Returns an item chosen randomly by weight (higher weights are more likely),
/// and replaces it so that it can be chosen again
/// </summary>
public TKey NextWithReplacement()
{
VerifyHaveItemsToChooseFrom();
if (_listNeedsRebuilding)
{
RebuildProbabilityList();
}
//Choose a random box, then flip a biased coin (represented by choosing a number of balls within the box)
int randomIndex = _random.Next(_probabilityBoxes.Count);
long randomNumBalls = _random.NextLong(_heightPerBox) + 1;
if (randomNumBalls <= _probabilityBoxes[randomIndex].NumBallsInBox)
{
return(_probabilityBoxes[randomIndex].Key);
}
else
{
return(_probabilityBoxes[randomIndex].Alias);
}
}