Btree (b-Tree)---C + +

The B-Tree of a M-order (M>2), is a balanced m-Path balanced search tree, which can be either empty tree or satisfy the nature:

1. Root node has at least two children

2. Each non-root node has [, M] Children

3. Each non-root node has a [ -1,m-1] keyword and is in ascending order

4. The value of the child node between Key[i] and key[i+1] is between Key[i], key[i+1]

5. All leaf nodes are on the same floor

PS: Is rounding up

#pragma  oncetemplate<class k, int m = 3>struct btreenode{k _keys [m];//  key word group btreenode<k, m>* _subs[m + 1];//  child array size_t _size;//   Number of keywords btreenode<k, m>* _parent;//  father Btreenode (): _size (0),  _parent (NULL) {for   (size_t i = 0; i < m + 1; ++i) {_subs[i] = NULL ;}}}; template<class k, class v>struct pair{k _first; v _second; Pair (Const k& k = k (),  const v& v = v ()): _first (K),  _second (v) {}};template<class k, int m = 3>class btree{typedef  Btreenode<k, m> node;public:btree (): _root (NULL) {}pair<node*, int> find (const  k& key) {node* parent = null; node* cur = _root;while  (cur) {int i = 0;while  (i&nbSp;< cur->_size && cur->_keys[i] < key) {++i;} if  (Cur->_keys[i] == key) {return pair<node*, int> (cur, i);} Parent = cur;cur = cur->_subs[i];} Return pair<node*, int> (parent, -1);} Bool insert (Const k& key) {if  (_root == null) {_root = new node ; _root->_keys[0] = key;++_root->_size;return true;} Pair<node*, int> ret = find (Key);if  (ret._second != -1) {return  false;} k k = key; node* cur = ret._first; node* sub = null;//  Inserts a kwhile  (1) {_insertkey (cur, k, sub);if  in the CUR node ( cur->_size < m) {return true;}   Split int boundary = m / 2; Node* tmp = new node;size_t index = 0;size_t size = cur-> _size;//&nbSP; copy keyfor  (int i = boundary + 1; i < size; ++i) {tmp- >_keys[index++] = cur->_keys[i];tmp->_size++;cur->_size--;}   Copy child node index = 0;for  (int i = boundary + 1; i <=  size; ++i) {tmp->_subs[index] = cur->_subs[i];if  (Tmp->_subs[index]) tmp-> _subs[index]->_parent = tmp;++index;} k = cur->_keys[boundary];cur->_size--;//  no Father if  (Cur->_parent == null) { _root = new node;_root->_keys[0] = k;_root->_subs[0] = cur;_root-> _subs[1] = tmp;_root->_size = 1;tmp->_parent = _root;cur->_parent  = _root;return true;} Cur = cur->_parent;sub = tmp;}} Void _insertkey (node* cur, const k& k, node* sub) {int i =  cur->_size - 1;while  (i >= 0) {if  (cur->_keys[i] > k) {cur->_keys[i +  1] = cur->_keys[i];cur->_subs[i + 2] = cur->_subs[i + 1 ];--i;} Else{break;}} cur->_keys[i + 1] = k;cur->_subs[i + 2] = sub;if  (sub) {sub- >_parent = cur;} cur->_size++;} Void inorder () {_inorder (_root); Cout << endl;} Void _inorder (Node* root) {if  (root == null) {return;} for  (size_t i = 0; i < root->_size; ++i) {_InOrder (root->_subs [i]); cout << root->_keys[i] <<  " ";} _inorder (Root->_subs[root->_size]);} protected:node* _root;}; Void testbtree1 () {btree<int, 1024> t1;int a[] = { 53, 75,  139, 49, 145, 36, 101 };for  (int i = 0; i  < sizeof (a)  / sizeof (a[0]);  ++i) {t1. Insert (A[i]);} T1. Inorder ();}

This article is from the "Wood Man" blog, please make sure to keep this source http://10324228.blog.51cto.com/10314228/1771019

Btree (b-Tree)---C + +