从上到下按层打印二叉树,同一层结点从左到右输出,每层输出一行
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};
//利用一个队列即可实现
class Solution {
public:
vector<vector<int> > Print(TreeNode* pRoot) {
vector<vector<int> > vec;
if(pRoot == NULL)
return vec;
queue<TreeNode *> q;
q.push(pRoot);
while(!q.empty()){
int sz = q.size();
vector<int> q1;
while(sz--){
TreeNode *p = q.front();
q.pop();
q1.push_back(p->val);
if(p->left)
q.push(p->left);
if(p->right)
q.push(p->right);
}
vec.push_back(q1);
}
return vec;
}
};