求二叉树中节点的最大距离

struct NODE
{
NODE* pLeft;        // 左子树
NODE* pRight;       // 右子树
int nMaxLeft;       // 左子树中的最长距离
int nMaxRight;      // 右子树中的最长距离
char chValue;       // 该节点的值
};

int nMaxLen = 0;

// 寻找树中最长的两段距离
void FindMaxLen(NODE* pRoot)
{
// 遍历到叶子节点。返回
if(pRoot == NULL)
{
return;
}

// 假设左子树为空，那么该节点的左边最长距离为0
if(pRoot -> pLeft == NULL)
{
pRoot -> nMaxLeft = 0;
}

// 假设右子树为空，那么该节点的右边最长距离为0
if(pRoot -> pRight == NULL)
{
pRoot -> nMaxRight = 0;
}

// 假设左子树不为空，递归寻找左子树最长距离
if(pRoot -> pLeft != NULL)
{
FindMaxLen(pRoot -> pLeft);
}

// 假设右子树不为空。递归寻找右子树最长距离
if(pRoot -> pRight != NULL)
{
FindMaxLen(pRoot -> pRight);
}

// 计算左子树最长节点距离
if(pRoot -> pLeft != NULL)
{
int nTempMax = 0;
if(pRoot -> pLeft -> nMaxLeft > pRoot -> pLeft -> nMaxRight)
{
nTempMax = pRoot -> pLeft -> nMaxLeft;
}
else
{
nTempMax = pRoot -> pLeft -> nMaxRight;
}
pRoot -> nMaxLeft = nTempMax + 1;
}

// 计算右子树最长节点距离
if(pRoot -> pRight != NULL)
{
int nTempMax = 0;
if(pRoot -> pRight -> nMaxLeft > pRoot -> pRight -> nMaxRight)
{
nTempMax = pRoot -> pRight -> nMaxLeft;
}
else
{
nTempMax = pRoot -> pRight -> nMaxRight;
}
pRoot -> nMaxRight = nTempMax + 1;
}

// 更新最长距离
if(pRoot -> nMaxLeft + pRoot -> nMaxRight > nMaxLen)
{
nMaxLen = pRoot -> nMaxLeft + pRoot -> nMaxRight;
}
}

public function getMaxDistance($node,&$Max){

if(null == $node){
return 0;
}

$left = $this->getMaxDistance($node->lchild,$Max);
$right = $this->getMaxDistance($node->rchild,$Max);

if($Max < ($left+$right)){
$Max = $left + $right;
}

return 1+($left>$right?

$left:$right);
}