Two-fork tree (i.)

A tree is a collection of elements of N (n>=0) finite data, shaped like an inverted tree.

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Two fork Tree : Two The fork tree is a special tree, with a maximum of two child nodes per node, called left child and right child, respectively.

full two fork tree: a two-fork tree with a height of N is a two-tree with 2^n-1 nodes.

Complete binary tree: If the depth of the two-fork tree is H, except for the H layer, the nodes of each layer (1~H-1) reach the maximum number, and all nodes of the H layer are continuously concentrated on the leftmost side, which is the complete binary tree

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The traversal of a tree

Example:

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Pre-sequence traversal (first root traversal): 1, first access to the root node, 2, the pre-order access to the left subtree, 3, the pre-order access to the right sub-tree; "1 2 3 4 5 6"

Middle Sequence Traversal: 1, middle sequence access to the left subtree, 2, access to the root node, 3, middle order access to the right sub-tree; 3 2 4 1 6 5 "

post-sequential traversal (after root traversal), 1, After the visit to the left sub-tree, 2, after the visit to the right subtree, 3, access to the root node; "3 4 2 6 5 1"

Sequence traversal: A layer of nodes traverses sequentially. "1 2 5 3 4 6"

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Template<class t>class binarytree{public:binarytree (): _root (NULL) {}binarytree (const T*  str, size_t size,const t& invalid) {size_t index = 0;_root =  _createtree (str, size,index, invalid);} BinaryTree (const binarytree<t>& b) {_root = _copy (b._root);} Binarytree<t>& operator= (binarytree<t> b) {swap (_root, b._root); return * this;} ~binarytree () {_destory (_root);} Protected:binarytreenode<t>* _createtree (const t* str, size_t size, size_t & index, const t& invalid) {        // The reference is to prevent fallback binarytreenode<t>* root = null;if  (index < size)  & &  (Str[index] != invalid)) {root = new binarytreenode<t> (Str[index]);// First construct the left subtree Root->_left = _createtree (STR,&NBSP;SIZE,&NBsp;++index, invalid);//Build Right subtree Root->_right = _createtree (str, size, ++index,  Invalid);} Return root;} Binarytreenode<t>* _copy (Const binarytreenode<t>* root) {if  (root) {       BinaryTreeNode<T>* newRoot = new BinaryTreeNode<T> ( Root->_data);   newroot->_left = _copy (root->_left);   newRoot->_right  = _copy (root->_right);   return newroot;} Return null;} Void _destory (binarytreenode<t>* root) {binarytreenode<t>* cur = root;if   (Root) {_destory (root->_left); _destory (root->_right);d Elete cur;cur = null;root  = null;} return;} protected:binarytreenode<t>* _root;};

Recursive traversal of a tree

Public:void prevorder ()   //pre-order recursive {_prevorder (_root); Cout << endl;} Void inorder ()     //in order recursive {_inorder (_root); Cout << endl;} Void postorder ()    //post-shipment recursion {_postorder (_root); Cout << endl;} Void levelorder ()    //sequence recursion {_levelorder (_root);} Protected:void _prevorder (Const binarytreenode<t>* root) {if  (Root == NULL) {return;} cout << root->_data <<  " "; _prevorder (Root->_left); _PrevOrder (root- >_right);} Void _inorder (Const binarytreenode<t>* root) {if  (root == null) {return;     }_inorder (root->_left);cout << root->_data <<  "   "; _inorder (root->_right); return;} Void _postorder (Const binarytreenode<t>* root) {if  (root == null) {return;} _postorder (Root->_left); _postorder (roOt->_right);cout << root->_data <<  " ";} Void _levelorder (binarytreenode<t>* root) {Queue<binarytreenode<t>*> q;q.push ( Root);while  (0 < q.size ()) {Binarytreenode<t>* tmp = q.front (); cout  << tmp->_data <<  " "; Q.pop ();if  (tmp->_left != null ) {Q.push (tmp->_left);} if  (tmp->_right != null) {Q.push (tmp->_right);}}}

VOID&NBSP;PREVORDER_NONR ()    //non-recursive pre-order {stack<binarytreenode<t>* > v1; V1.push (_root); Binarytreenode<t>* cur = _root;cout << v1.top ()->_data <<   " ";while  (!v1.empty ()) {V1.pop ();if  (cur->_right) {V1.push (cur->_right);} if  (cur->_left) {V1.push (cur->_left);} if  (V1.size ()  == 0) {return;} Cout << v1.top ()->_data <<  " "; Cur = v1.top ();} VOID&NBSP;INORDER_NONR ()    //non-recursive middle order {stack<binarytreenode<t>* > v2; binarytreenode<t>* cur = _root;while  (cur| |! V2.empty ()) {while  (cur) {v2.push (cur); cur = cur->_left;} Cout << v2.top ()->_data <<  " "; Binarytreenode<t>* top = v2.top (); V2.pop (); cur = top->_right;}} VOID&NBSP;POSTORDER_NONR ()      //non-recursive post-shipment {BINARYTReenode<t>* cur = _root; Binarytreenode<t>* prev = null;stack<binarytreenode<t>* > s;while   (cur | |  !s.empty ()) {while  (cur) {s.push (cur); cur = cur->_left;} Binarytreenode<t>* top = s.top ();if  (top->_right == null | |  top->_right == prev) {cout << top->_data <<  " "; S.pop ();p rev = top;} Else{cur = top->_right;}}}

tree size, depth ....

       size_t size () Size of    //tree {size_t size =  _size (_root); return size;} Size_t depth () Depth of    //tree {size_t dep = _depth (_root); return dep;} Size_t leafsize () Number of     //leaf nodes {size_t count = _leafsize (_root); return  count;} Binarytreenode<t>* find (const t& d)     //find Node {return _Find (_ ROOT,&NBSP;D);} How many nodes/*size_t getklevel (const size_t& k) {return _getklevel (_root, k) are there on level k?} */size_t getklevel (const size_t& k) {Size_t level = 1;_getklevel (_root,  1evel, k, size); return size;} Size_t _size (Const binarytreenode<t>* root) {size_t size = 1;if  (root= =null) {return 0;} Size += _size (Root->_left); size += _size (root->_right); return size;} Size_t _dePTH (const binarytreenode<t>* root) {size_t dep1 = 1;size_t dep2 =  1;if  (root == null) {return 0;} Dep1 += _depth (Root->_left);d ep2 += _depth (root->_right);if  (dep1 > &NBSP;DEP2) {return dep1;} ELSE{RETURN&NBSP;DEP2;}} Size_t _leafsize (const binarytreenode<t>* root) {size_t count = 0;if  ( Root == null) {return 0;} if  ((root->_left == null)  &&  (root->_right == null)) {return  1;} Count += _leafsize (Root->_left); count += _leafsize (root->_right); return count;} Binarytreenode<t>* _find (binarytreenode<t>* root, const t& d) {if   (root == null) {return null;} if  (root->_data == d) {return root;} Binarytreenode<t>* ret = _find (root->_left, d);if  (ret) {REturn ret;} Return _find (root->_right, d);} /*size_t _getklevel (binarytreenode<t>* root, size_t k) {if  (root ==  NULL) {return 0;} if  (k == 1) {return 1;} Return _getklevel (root->_left, k - 1)  + _getklevel (root->_right, k &NBSP;-&NBSP;1);} */void _getklevel (binarytreenode<t>* root, size_t level, size_t k,  size_t& size) {if  (root == null) {return;} if  (k == level) {Size++;return;} _getklevel (root->_left, level + 1, k, size); _getklevel (root->_right, level  + 1, k, size);}

The next article will introduce you to the clues of the tree, write bad please teach Oh oh oh oh ~650) this.width=650; "src=" Http://img.baidu.com/hi/jx2/j_0002.gif "alt=" J_0002.gif " />

Two-fork tree (i.)