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) {
    }
};
*/

// 广搜BFS
class Solution {
public:
        vector<vector<int> > Print(TreeNode* pRoot) {
            vector<vector<int>> res;
            if (pRoot == NULL) return res;
            queue<TreeNode*> q;
            q.push(pRoot);
            vector<int> tmp;
            while (!q.empty()) {
                int size = q.size();
                tmp.clear();
                for (int i = 0; i < size; ++i) {
                    TreeNode* node = q.front();
                    tmp.push_back(node->val);
                    q.pop();
                    if (node->left) q.push(node->left);
                    if (node->right) q.push(node->right);
                }
                res.push_back(tmp);
            }
            return res;
        }
    
};