剑指offer——二叉树的深度与平衡二叉树的判断

通过后续遍历，可以减少重复访问

 #include <iostream>
 #include <string>
 using namespace std;

 struct BinaryTreeNode
 {
     int m_data;
     BinaryTreeNode* m_left;
     BinaryTreeNode* m_right;
 };

 int TreeDepth(BinaryTreeNode* pRoot)
 {
     if (pRoot==NULL)
     {
         return ;
     }
     int nleft=TreeDepth(pRoot->m_left);
     int nright=TreeDepth(pRoot->m_right);
     return (nleft>nright)?(nleft+):(nright+);
 }

 bool IsBalance(BinaryTreeNode* pRoot,int *pDepth)
 {
     if (pRoot==NULL)
     {
         *pDepth=;
         return true;
     }
     int left,right;
     if(IsBalance(pRoot->m_left,&left)&&IsBalance(pRoot->m_right),&right)
     {
         int diff=left-right;
         if (diff<=&&diff>=-)
         {
             *pDepth=+(left>right)?left:right;
             return true;
         }
     }
     return false;
 }