# 剑指offer---按只字形顺序打印二叉树

```class Solution
{
public:
vector<vector<int> > Print(TreeNode* pRoot)
{

TreeNode* cur = pRoot;
stack<TreeNode*> stack1_LeftToRight;
stack<TreeNode*> stack2_RightToLeft;
stack1_LeftToRight.push(pRoot);
vector<vector<int> > result;
if (pRoot == NULL)    return result;
while ((!stack1_LeftToRight.empty()) || (!stack2_RightToLeft.empty()))
{
vector<int> re;
if( (!stack1_LeftToRight.empty()) && (stack2_RightToLeft.empty()))
{
while (!stack1_LeftToRight.empty())
{
TreeNode* cur= stack1_LeftToRight.top();
if(cur->left!=NULL) stack2_RightToLeft.push(cur->left);
if(cur->right!=NULL) stack2_RightToLeft.push(cur->right);
re.push_back(cur->val);
stack1_LeftToRight.pop();
}
result.push_back(re);
}
else
{
while (!stack2_RightToLeft.empty())
{
TreeNode* cur = stack2_RightToLeft.top();
if(cur->right!=NULL) stack1_LeftToRight.push(cur->right);
if(cur->left!=NULL) stack1_LeftToRight.push(cur->left);
re.push_back(cur->val);
stack2_RightToLeft.pop();
}
result.push_back(re);
}
re.clear();
}
return result;

}

};```