题解 | #把二叉树打印成多行#

struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
*/
class Solution {
public:
        vector<vector<int> > Print(TreeNode* pRoot) {
        vector<vector<int> >ret;
        if(!pRoot)return ret;
            queue<TreeNode*>q;
            q.push(pRoot);//bfs
            while(!q.empty()){
                int n=q.size();
                vector<int>temp;
                for(int i=0;i<n;i++){//可以一层一层遍历
                    TreeNode* treenode=q.front();
                    temp.push_back(treenode->val);
                    q.pop();
                    if(treenode->left)
                    q.push(treenode->left);
                    if(treenode->right)
                    q.push(treenode->right);
                }
                ret.push_back(temp);
            }
            return ret;
        }
    
};