剑指60-把二叉树打印成多行

#include<queue>
#include<vector>

using namespace std;

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> > res;
        if (!pRoot) return res;
        int num = 0;
        node_queue.push(pRoot);
        num++;//当前个数
        while (!node_queue.empty())
        {
            int num_temp = 0; //子树个数
            vector<int> temp_vec;
            for (int i = 0; i < num; i++)
            {
                TreeNode* temp_node = node_queue.front();
                node_queue.pop();
                if (temp_node->left)
                {
                    node_queue.push(temp_node->left);
                    num_temp++;
                }
                if (temp_node->right)
                {
                    node_queue.push(temp_node->right);
                    num_temp++;
                }
                temp_vec.push_back(temp_node->val);
            }
            res.push_back(temp_vec);
            num = num_temp;
        }

        return res;
    }

private:
    queue<TreeNode*> node_queue;
};