private TreeDictionary <TKey, TValue, TComparer> AddRecursive(TKey key, TValue value, Func <TValue, TValue> combiner, ref bool needRebalance)
{
if (_count == 0)
{
needRebalance = true;
return(TreeDictionary.Single <TKey, TValue, TComparer>(key, value));
}
int comparison = _Comparer.Compare(key, _key);
if (comparison == 0)
{
needRebalance = false;
return(ReplaceValue(combiner(_value)));
}
if (comparison < 0)
{
var dict = _left.AddRecursive(key, value, combiner, ref needRebalance);
return(needRebalance
? NearlyBalanced(dict, _right)
: Balanced(dict, _right));
}
else
{
var dict = _right.AddRecursive(key, value, combiner, ref needRebalance);
return(needRebalance
? NearlyBalanced(_left, dict)
: Balanced(_left, dict));
}
}