剑指offer---把二叉树打印成多行

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。

/*
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
*/
class Solution {
    vector<vector<int> > res;
public:
        vector<vector<int> > Print(TreeNode* pRoot) {
            if(!pRoot)
                return res;
            queue<TreeNode*> que;
            que.push(pRoot);
            while(!que.empty()){
                vector<int> v;
                int s=que.size();
                TreeNode* node=nullptr;
                for(int i=0;i<s;++i){
                    node=que.front();
                    v.push_back(node->val);
                    que.pop();
                    if(node->left) que.push(node->left);
                    if(node->right) que.push(node->right);
                }
                res.push_back(v);
            }
            return res;
        }
};