c++

/*
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> > result;
        if (pRoot == NULL) return result;
        queue<TreeNode *> que;
        que.push(pRoot);
        while(!que.empty()) {
            int len = que.size();
            vector<int> level;
            while(len--) {
                TreeNode* node = que.front();
                que.pop();
                level.push_back(node->val);
                if (node->left) que.push(node->left);
                if (node->right) que.push(node->right);
            }
            result.push_back(level);
        }
        return result;
    }
};