二叉树的创建
//index要给引用！！！
void _Create(Node *&pRoot,T *arr,T invalid,size_t sz,size_t &index)
{
if (arr[index] != invalid&&index < sz)
{
pRoot = new Node(arr[index]);
_Create(pRoot->_pLeft, arr, invalid, sz, ++index);
_Create(pRoot->_pRight, arr, invalid, sz, ++index);
}
}
二叉树的递归遍历
void _Order(Node *pRoot)
{
if (NULL != pRoot)
{
cout << pRoot->_data << " ";//前序
_Order(pRoot->_pLeft);
//cout << pRoot->_data << " ";//中序
_Order(pRoot->_pRight);
//cout << pRoot->_data << " ";//后序
二叉树的非递归遍历
- 前序遍历
void _PreOrder_Nor(Node *pRoot)
{
stack<Node *> st;
//要记得加上pRoot存在的情况下，防止右单支存在的情况同时防止空树
while (pRoot||!st.empty())
{
while (pRoot)
{
cout << pRoot->_data<< " ";
st.push(pRoot);
pRoot = pRoot->_pLeft;
}
Node *pTop = st.top();
st.pop();
pRoot = pTop->_pRight;
}
}
- 中序遍历
void _InOrder_Nor(Node *pRoot)
{
stack<Node *> st;
while (pRoot||!st.empty())
{
while (pRoot)
{
st.push(pRoot);
pRoot = pRoot->_pLeft;
}
Node *pTop = st.top();
cout << pTop->_data << " ";
st.pop();
pRoot = pTop->_pRight;
}
}
- 后续遍历：
void _PostOrder(Node *pRoot)
{
stack<Node *> st;
//给个flag,标记节点是否被访问过
Node *pPreNode=NULL;
while (pRoot || !st.empty())
{
while (pRoot)
{
st.push(pRoot);
pRoot = pRoot->_pLeft;
}
Node *pTop = st.top();
if (NULL == pTop->_pRight||pPreNode==pTop->_pRight)
{
cout << pTop->_data<<" ";
pPreNode = pTop;
st.pop();
}
//如果右边不为空或者右边没有被访问过，则向右边拐
else
4.层序遍历：
void _LevelOrder(Node *pRoot)
{
if (NULL == pRoot)
return;
queue<Node *> q;
q.push(pRoot);
while (!q.empty())
{
Node *pTop = q.front();
cout << pTop->_data << " ";
if (pTop->_pLeft)
q.push(pTop->_pLeft);
if
