private IBNode DeleteLeaf(int value, IBNode tree)
{
BLeaf leaf = (BLeaf)tree;
bool res = leaf.RemoveValue(value);
if (res)
{
if (leaf.GetChildrenNum() < Math.Ceiling(M / 2m))
{
BNode parent = leaf.Parent;
if (parent == null)
{
}
else
{
//先找到孩子节点
var siblings = parent.GetSiblings(leaf);
if (siblings.Count == 0)
{//非孩子节点
//do nothing
}
else
{
IBNode sibling = null;
foreach (var node in siblings)
{
if (node.GetChildrenNum() > Math.Ceiling(M / 2m))
{
sibling = node;
break;
}
}
if (sibling == null)
{//兄弟节点都没有多的元素
MergeLeaf((BLeaf)siblings[0], leaf);
//开始检索上级
parent = (BNode)DeleteNode(parent);
}
else
{
ShareLeafValue((BLeaf)sibling, leaf);
}
}
}
}
else
{//do nothing
}
}
else
{//节点不存在
}
return(tree);
}
private void ShareLeafValue(BLeaf leftLeaf, BLeaf rightLeaf)
{
int value = 0;
if (leftLeaf.GetMinKey() < rightLeaf.GetMinKey())
{
int i = leftLeaf.GetChildrenNum() - 1;
value = leftLeaf.Values[i];
}
else
{
value = leftLeaf.GetMinKey();
}
rightLeaf.AddValue(value);
leftLeaf.RemoveValue(value);
}