题目描述
从上到下按层打印二叉树,同一层结点从左至右输出。每一层输出一行。
思路
利用队列的思想
代码
class Solution {
public:
vector<vector<int> > Print(TreeNode* pRoot) {
vector<vector<int> > res;
vector<int> res_p;
if(pRoot == NULL)
return res;
queue<TreeNode*> q_Tree;
q_Tree.push(pRoot);
res_p.push_back(pRoot->val);
res.push_back(res_p);
res_p.clear();
int count = 1;
while(q_Tree.size()>0)
{
int number = q_Tree.size();
while(number > 0)
{
TreeNode* current = q_Tree.front();
q_Tree.pop();
if(current->left)
{
q_Tree.push(current->left);
res_p.push_back(current->left->val);
}
if(current->right)
{
q_Tree.push(current->right);
res_p.push_back(current->right->val);
}
number--;
}
if(res_p.size()>0)
{
res.push_back(res_p);
res_p.clear();
}
count++;
}
return res;
}
};