Data Structure Basics (19)--design and implementation of red and Black trees (2)

Double Rotation

Single rotation sometimes occurs with a problem (as shown):

(If the inner descendant node [K1] is too deep, moving it one-way will not solve the problem)

So there's a double spin.

Double rotation to the right:

1. First take K1 as the axis, K1 and K2 rotate to the left;

2. Then take K3 as the axis, K3 and rotate the K1 to the right;

Implement//Right double rotate template <typename type>void redblacktree<type>::d oublerotatewithleftchild (Node *& K3) const{    //First turn its left son (K1) to the left single rotation    rotatewithrightchild (k3->left);    Then turn yourself (K3) to the right single-spin    rotatewithleftchild (K3);}

Double rotation to the left:

1. First Take K3 as the axis , K2 and K3 rotate to the right ;

2. Then take K1 as the axis , K1 and rotate the K2 to the left ;

Implement//Left double rotate template <typename type>void redblacktree<type>::d oublerotatewithrightchild (Node *& K1) const{    //First turn its right son (K2) to the right by single rotation    rotatewithleftchild (k1->right);    Then turn yourself (K1) to the left single-spin    rotatewithrightchild (K1);} Note: In fact, the red and black trees do not use the double rotation, but their own implementation of a rotate operation,//In this only to learn the theory of double rotation;

Test (after completing the double rotation):

(Constructs a binary lookup tree, the left side is not rotated before, the right is rotated, the axis is double rotated by 8)

int main () {//uses Neg_inf to represent the negative Infinity const int neg_inf =-999999;    Redblacktree<int> tree (Neg_inf);//test data for double rotation tree.insert (12);    Tree.insert (16);    Tree.insert (8);    Tree.insert (10);    Tree.insert (4);    Tree.insert (14);    Tree.insert (2);    Tree.insert (6);    Tree.insert (5);    cout << tree.header->right->element << Endl;  cout << tree.header->right->left->element << Endl; 8 cout << tree.header->right->right->element << Endl;    cout << tree.header->right->left->left->element << Endl;   4 cout << tree.header->right->left->right->element << Endl;   Ten cout << tree.header->right->right->left->element << Endl;   14//cout << tree.header->right->left->right->left->element << Endl; 5 have been Sentinel//cout << tree.header->right->left->right->right->element << endl  5 cout << tree.header->right->left->left->left->element << Endl; 2 cout << tree.header->right->left->left->right->element << Endl;   6 cout << tree.header->right->left->left->right->left->element << Endl;    5 cout << "\ n Double turn" << Endl;    Double rotation tree.doublerotatewithleftchild (tree.header->right->left) to the right with 8 as the benchmark;    cout << tree.header->right->element << Endl;  cout << tree.header->right->left->element << Endl; 6 cout << tree.header->right->right->element << Endl;    cout << tree.header->right->left->left->element << Endl;   4 cout << tree.header->right->left->right->element << Endl; 8 cout << tree.header->right->right->left->element << Endl; cout << Tree.header->right->left->leFt->left->element << Endl;  2 cout << tree.header->right->left->left->right->element << Endl;    5 cout << tree.header->right->left->right->right->element << Endl; return 0;}

Exception

Exception constructs used during the implementation of the red-black Tree: Class Dsexception{public:    dsexception (const string &_message = String ())        : Message (_ Message) {}    ~dsexception () {}    Virtual string what () const    {        return message;    }    Virtual string toString () const    {        return "Exception:" + what ();    } Private:    std::string message;}; Class Duplicateitemexception:public Dsexception{public:    duplicateitemexception (const string &_msg = String ( )        : Dsexception (_msg) {}};

Data Structure Basics (19)--design and implementation of red and Black trees (2)