[Algorithm] binary tree creation

"Chained storage Structure"

struct TreeNode {    int val;    TreeNode *left;    TreeNode *right;    TreeNode (int x): Val (x), left (null), right (null) {}};

"Hierarchy Create two fork tree"

Create two fork Tree treenode* createtreebylevel (vector<char> num) {    int len = Num.size ();    if (len = = 0) {        return NULL;    } If    queue<treenode*> queue;    int index = 0;    Create root node    TreeNode *root = new TreeNode (num[index++]);    Into the queue    Queue.push (root);    TreeNode *p = NULL;    while (!queue.empty () && Index < len) {        //out queue        p = Queue.front ();        Queue.pop ();        Left node        if (Index < len && Num[index]! =-1) {            //If not empty create a node            TreeNode *leftnode = new TreeNode (num[ Index]);            P->left = Leftnode;            Queue.push (Leftnode);        }        index++;        Right node if        (Index < len && Num[index]! =-1) {            //If not empty create a node            TreeNode *rightnode = new TreeNode (num [index]);            P->right = Rightnode;            Queue.push (Rightnode);        }        index++;    }    while return root;}

-1 represents NULL

Create a two fork tree input as above:

15 11 20 8 14-1-1-1-1 13-1

"First order Create two fork tree"

Creates a two  -fork-Tree int createbtree (treenode*& T) {      int data,      in order sequence; Enter the value of the node in the binary tree in order, 1 means empty tree      cin>>data;      if (data = =-1) {          T = NULL;      }      else{          T = new TreeNode (data);          Constructs left subtree          createbtree (t->left);          Construct right subtree          createbtree (t->right);      }      return 0;  

-1 represents null

Create a two fork tree input as above:

15 11 8-1-1 14 13-1-1-1 20-1-1

[Algorithm] binary tree creation