if (child)
{
child->parent = parent;
}
if (parent)
{
if (parent->left == node)
{
parent->left = child;
}
else
{
parent->right = child;
}
}
else
{
root = child;
}

if (node->parent == old)
{
parent = node;
}

node->parent = old->parent;
node->color = old->color;
node->right = old->right;
node->left = old->left;

if (old->parent)
{
if (old->parent->left == old)
{
old->parent->left = node;
}
else
{
old->parent->right = node;
}
}
else
{
root = node;
}

old->left->parent = node;
if (old->right)
{
old->right->parent = node;
}
}
else
{
if (!node->left)
{
child = node->right;
}
else if (!node->right)
{
child = node->left;
}
parent = node->parent;
color = node->color;

if (child)
{
child->parent = parent;
}
if (parent)
{
if (parent->left == node)
{
parent->left = child;
}
else
{
parent->right = child;
}
}
else
{
root = child;
}
}

free(old);
--useCount;
if (color == BLACK)
{
root = rb_erase_rebalance(child, parent, root);
}

return root;
}

摘自 C++ 技术中心