careercup4.3

插入最中点

/*Given a sorted (increasing order) array, write an algorithm to create a binary tree with minimal height */#include <iostream>#include <queue>using namespace std;class Node{public:int data;    Node *lchild,*rchild;Node(int a=0, Node* l= 0, Node* r = 0):data(a),lchild(l),rchild(r){}};class Tree{public:Node* root;Tree():root(0){}Tree(int ar[],int l){root = 0;for(int i = 0; i<l; i++)insert(ar[i]);}void insert(int);bool is_empty(){ return !root;}int height(Node*);void preorder(Node*,int);void destroy(Node*);void traorder(Node*);Node* treebuild(int[],int,int);};void Tree::insert(int k){if(is_empty())root = new Node(k);else{Node* temp = root;Node* parent;while(temp){parent =temp;if(temp->data > k)temp = temp->lchild;else temp = temp->rchild;}temp = new Node(k);if(parent->data > k)parent->lchild = temp;else parent->rchild = temp;}}void Tree::preorder(Node* r,int d){if(r){preorder(r->lchild, d+1);cout<<r->data<<" ";preorder(r->rchild, d+1);}}int Tree::height(Node* r){if(!r)return 0;else{int hr = height(r->rchild);int hl = height(r->lchild);return hr > hl ? hr+1 : hl+1;}}void Tree::destroy(Node* r){if(r){destroy(r->lchild);destroy(r->rchild);delete r;}}//print tree level by levelvoid Tree::traorder(Node* r){if(!r) return;queue<Node*> q;q.push(r);Node* temp;Node* level = 0;while(!q.empty()){temp = q.front();//whenever meet the next level, change to the next line.if(temp == level){cout<<endl;level = 0;}cout<<temp->data<<" ";if(temp->data == 7)int i =1;q.pop();//keep track of the first time when this level's children are pushed into the queue.if (temp->lchild != NULL) {  q.push(temp->lchild);if(!level) level = temp->lchild;}if (temp->rchild != NULL){ q.push(temp->rchild);if(!level) level = temp->rchild;   }}cout<<endl;}Node* Tree::treebuild(int ar[], int b, int e){if (b > e) return NULL;int k = (b+e)/2;root = new Node(ar[k],treebuild(ar,b,k-1),treebuild(ar,k+1,e));return root;}int main(){int ar[]={1,2,3,4,5,6,7,8,9,10,11,22,32};Tree ll;ll.treebuild(ar,0,12);ll.traorder(ll.root);ll.destroy(ll.root);}