#include "StdAfx.h"
#include "My_Rb_Tree.h"
#include "assert.h"
My_Rb_Tree::My_Rb_Tree(void)
:node_count(0),
head(0)
{
Init();
}
My_Rb_Tree::~My_Rb_Tree(void)
{
}
node * My_Rb_Tree::Root()
{
assert(head);
if (!head)
{
return 0;
}
return head->parent;
}
void My_Rb_Tree::Init()
{
head = CreateNode(0);
if (!head)
{
return;
}
head->color = node_red;
head->left = head;
head->right = head;
head->parent = 0;
}
node * My_Rb_Tree::CreateNode(value_type _val)
{
node * n = new node;
n->parent = 0;
n->left = 0;
n->right = 0;
n->color = node_red;
n->val = _val;
return n;
}
void My_Rb_Tree::DestoryNode(node * &_n)
{
delete _n;
_n = 0;
}
void My_Rb_Tree::RotateLeft(node * _cur)
{
node * _root = Root();
node * r = _cur->right;
if (!r)
{
return;
}
if ( _cur ==_root )
{
_root = r;
r->parent = _cur->parent;
_cur->parent->parent = r;
}
else
{
}
r->parent = _cur->parent;
if (_cur->parent->left == _cur)
{
r->parent->left = r;
}
else
{
r->parent->right = r;
}
_cur->right = r->left;
if (r->left)
{
_cur->right->parent = _cur;
}
r->left = _cur;
_cur->parent = r;
}
void My_Rb_Tree::RotateRight(node * _cur)
{
node * _root = Root();
node * l = _cur->left;
if (!l)
{
return;
}
if ( _cur == _root )
{
_root = l;
l->parent = _cur->parent;//head
l->parent->parent = l;// head->parent
}
else
{
l->parent = _cur->parent;
if (l->parent->left == _cur)
{
l->parent->left = l;
}
else
{
l->parent->right = l;
}
}
_cur->left = l->right;
if (l->right)
{
_cur->left->parent = _cur;
}
l->right = _cur;
_cur->parent = l;
}
void My_Rb_Tree::Rebalance(node * _cur)
{
node * _root = Root();
_cur->color = node_red;
if (_cur->parent == head) // _cur is root node
{
_cur->color = node_black;
return;
}
if ( _cur->parent->color == node_black ) // now is balance state.
{
return ;
}
// 根据原来的树是符合红黑规则，祖父节点必定为黑色
while( (_cur != Root()) && (_cur->parent->color == node_red)) // 当前节点的父节点为红色，违反规则
{
if (_cur->parent->parent->left == _cur->parent) // 父节点为左子节点
{
if(_cur->parent->parent->right
&& _cur->parent->parent->right->color == node_red) // 伯父节点为红
{
// 把父节点和伯父节点变成黑色，祖父节点变成红色
_cur->parent->parent->right->color=node_black;
_cur->parent->color = node_black;
_cur->parent->parent->color = node_red;
// 因为祖父节点为红色，需要继续向上测试是否满足规则
_cur = _cur->parent->parent;
continue;
}
else // 伯父节点为黑或不存在
{
if ( _cur == _cur->parent->right )
{
// 以父节点为轴，左旋转后变成两个左外节点连续为红。
_cur = _cur->parent;
RotateLeft(_cur/*,_root*/);
}
// 改变颜色，以祖父节点为轴，右旋转。
_cur->parent->parent->color = node_red;
_cur->parent->color = node_black;
RotateRight(_cur->parent->parent/*,_root*/);
// 此时进入下一次while判断跳出循环
}
}
else // 父节点为右子节点，依照左子节点的同样方法解决。
{
if(_cur->parent->parent->left
&& _cur->parent->parent->left->color == node_red) // 伯父节点为红
{
// 把父节点和伯父节点变成黑色，祖父节点变成红色
_cur->parent->parent->left->color=node_black;
_cur->parent->color = node_black;
_cur->parent->parent->color = node_red;
// 因为祖父节点为红色，需要继续向上测试是否满足规则
_cur = _cur->parent->parent;
continue;
}
else // 伯父节点为黑或不存在
{
if ( _cur == _cur->parent->left )
{
// 以父节点为轴，右旋转后变成两个右外节点连续为红。
_cur = _cur->parent;
RotateRight(_cur/*,_root*/);
}
// 改变颜色，以祖父节点为轴，左旋转。
_cur->parent->parent->color = node_red;
_cur->parent->color = node_black;
RotateLeft(_cur->parent->parent/*,_root*/);
// 此时进入下一次while判断跳出循环
}
}
}//end while
_root->color = node_black;
}
node * My_Rb_Tree::InsertUnique(value_type in_val)
{
node * y = head;
node * x = Root();
bool comp = true;
while( x )//一层一层深入找到合适的插入点
{
y = x;
comp = ( in_val < x->val );
if (in_val == x->val)
{
return 0;
}
x = comp x->left : x->right;
}
return Insert(y,x,in_val);
}
node * My_Rb_Tree::Insert(node * in_parent, node * in_cur, value_type in_value)
{
node * new_node = CreateNode(in_value);
if (in_parent == head) // 插入的是根节点
{
head->parent = new_node;
head->left = new_node;
head->right = new_node;
new_node->parent = head;
new_node->color = node_black;
}
else // 插入的是非根节点
{
if ( new_node->val < in_parent->val )
{
in_parent->left = new_node;
if (in_parent == head->left) // 若插入点的父节点是最小节点，更新最小值节点指针
{
head->left = new_node;
}
}
else
{
in_parent->right = new_node;
if (in_parent == head->right)// 若插入点的父节点是最大节点，更新最大值节点指针
{
head->right = new_node;
}
}
new_node->parent = in_parent;
if (in_parent == head)
{
head->parent = new_node;
in_parent->parent = Root();
}
}
Rebalance(new_node/*,head->parent*/);
node_count++;
return new_node;
}
// 未实现，这个函数比较复杂
void My_Rb_Tree::RebalanceForErase(node * _cur)
{
return;
}
// 依赖RebalanceForErase的实现
void My_Rb_Tree::Erase(node * in_cur)
{
return;
}
node * My_Rb_Tree::Find(value_type _val)
{
node * _t = Root();
while(_t)
{
if (_t->val == _val)
{
return _t;
}
else if (_t->val > _val)
{
_t = _t->right;
}
else
{
_t = _t->left;
}
}
return 0;
}