CareerCup-4.1

Implement a function to check if a tree is balanced For the purposes of this question, 
a balanced tree is defined to be a tree such that no two leaf nodes differ in distance 
from the root by more than one 

答案是两次遍历分别求出最大深度与最小深度，我试着一次遍历求出最大和最小深度

#include <iostream>using namespace std;typedef int Data;struct TreeNode{    TreeNode(Data d):data(d){left = right = NULL;};    Data data;    TreeNode* left;    TreeNode* right;};class Tree{public:    Tree():root(NULL){};    TreeNode* root;    void insert(Data data, TreeNode* node = NULL)    {        if(root == NULL)        {            root = new TreeNode(data);            return;        }        if(node == NULL) node = root;        if(data == node->data)        {            return;        } else if(data < node->data) {            if(node->left == NULL)                node->left = new TreeNode(data);                else                insert(data, node->left);        } else {            if(node->right == NULL)                node->right = new TreeNode(data);            else                insert(data, node->right);        }    };    void inorderPrint(TreeNode* TreeNode)    {        if(TreeNode == root)            cout<<"Print:"<<endl;        if(TreeNode != NULL)        {            inorderPrint(TreeNode->left);            cout<<TreeNode->data<<" ";            inorderPrint(TreeNode->right);        }        if(TreeNode == root)            cout<<endl<<"End"<<endl;    };    void preorderPrint(TreeNode* TreeNode)    {        if(TreeNode == root)            cout<<"Print:"<<endl;        if(TreeNode != NULL)        {            cout<<TreeNode->data<<" ";            preorderPrint(TreeNode->left);            preorderPrint(TreeNode->right);        }        if(TreeNode == root)            cout<<endl<<"End"<<endl;    };    void postorderPrint(TreeNode* node)    {        if(node == root)            cout<<"Print:"<<endl;        if(node != NULL)        {            postorderPrint(node->left);            postorderPrint(node->right);            cout<<node->data<<" ";        }        if(node == root)            cout<<endl<<"End"<<endl;    };    bool isBalanced()    {        int min=0 ,max=0;        calDepth(root, 0, &min, &max);        cout<<"Min: "<<min<<endl<<"Max: "<<max<<endl;        if(max - min < 2)            return true;        else            return false;    };    void calDepth(TreeNode* node, int depth, int* min, int* max)    {        if(node == NULL) return;        depth++;        if(node->left == NULL && node->right == NULL)        {            if(depth < *min || *min <= 0)                *min = depth;            if(depth > *max || *max <= 0)                *max = depth;        }        calDepth(node->left, depth, min, max);        calDepth(node->right, depth, min, max);    };};int main(){    Tree tree;    tree.insert(5);    tree.insert(1);    tree.insert(7);    tree.insert(4);    tree.insert(3);    cout<<boolalpha<<tree.isBalanced();    system("pause");};