[编程之美-17]求二元树的度

题目：输入一棵二元树的根结点，求该树的深度。 
从根结点到叶结点依次经过的结点（含根、叶结点）形成树的一条路径，最长路径的长度为树的深度。 
例如：输入二元树： 
8 
/ / 
6 10 
// // 
5 7 9 11 
输出该树的深度3。 

二元树的结点定义如下：

struct SBinaryTreeNode // a node of the binary tree{      int               m_nValue; // value of node      SBinaryTreeNode  *m_pLeft;  // left child of node      SBinaryTreeNode  *m_pRight; // right child of node};

思想：同[编程之美-16]主要考察还是层序遍历思想。

代码如下：

#include<iostream>#include<deque>using namespace std;struct BSTreeNode{    int m_nValue;    BSTreeNode *m_pleft;    BSTreeNode *m_pright;};int depthOfBSTree = 0;void addBSTreeNode(BSTreeNode *&pCurrent, int value);void levelOrderBSTree(BSTreeNode *pRoot);int main(){    BSTreeNode *pRoot = NULL;    addBSTreeNode(pRoot, 8);    addBSTreeNode(pRoot, 6);    addBSTreeNode(pRoot, 5);    addBSTreeNode(pRoot, 7);    addBSTreeNode(pRoot, 10);    addBSTreeNode(pRoot, 9);    addBSTreeNode(pRoot, 11);    levelOrderBSTree(pRoot);    cout<<depthOfBSTree<<endl;    return 0;}void levelOrderBSTree(BSTreeNode *pRoot){    if(pRoot == NULL)        return ;    deque<BSTreeNode*> que;    que.push_back(pRoot);    BSTreeNode *last, *nlast;    last = pRoot;    nlast = pRoot;    while(que.size() != 0)    {        BSTreeNode *pCurrent = que.front();        que.pop_front();        if(pCurrent->m_pleft != NULL)        {            nlast = pCurrent->m_pleft;            que.push_back(pCurrent->m_pleft);        }        if(pCurrent->m_pright != NULL)        {            nlast = pCurrent->m_pright;            que.push_back(pCurrent->m_pright);        }        if(pCurrent == last)        {            depthOfBSTree ++;            last = nlast;        }    }}void addBSTreeNode(BSTreeNode *&pCurrent, int value){    if(pCurrent == NULL)    {        BSTreeNode *pBSTree = new BSTreeNode();        pBSTree->m_nValue = value;        pBSTree->m_pleft = NULL;        pBSTree->m_pright = NULL;        pCurrent = pBSTree;    }    else    {        if((pCurrent->m_nValue) > value)            addBSTreeNode(pCurrent->m_pleft, value);        else if((pCurrent->m_nValue) < value)            addBSTreeNode(pCurrent->m_pright, value);       }}