每日一题(74) - 求二叉树中节点的最大距离

struct BTNode
{
	int m_nData;
	BTNode* m_pLeft;
	BTNode* m_pRight;
};

int MaxDistance(BTNode* pRoot,int& nMaxDist)
{
	if (!pRoot)
	{
		return 0;
	}
	int nLeftDept = MaxDistance(pRoot->m_pLeft,nMaxDist);
	int nRightDept = MaxDistance(pRoot->m_pRight,nMaxDist);
	nMaxDist = max(nLeftDept + nRightDept,nMaxDist);
	return max(nLeftDept,nRightDept) + 1;
}