题目

    1. /*
    2. struct TreeNode {
    3.     int val;
    4.     struct TreeNode *left;
    5.     struct TreeNode *right;
    6.     TreeNode(int x) :
    7.             val(x), left(NULL), right(NULL) {
    8.     }
    9. };
    10. */
    11. class Solution {
    12. public:
    14.     vector<vector<int>> ans;
    15.     vector<vector<int>> Print(TreeNode *pRoot) {
    16.         if (pRoot == nullptr) return ans;
    17.         queue<TreeNode *> queue;
    18.         queue.push(pRoot);
    19.         while (!queue.empty()) {
    20.             int size = queue.size();
    21.             vector<int> tmp;
    22.             for (int i = 0; i < size; i++) {
    23.                 TreeNode *front = queue.front();
    24.                 tmp.push_back(front->val);
    25.                 queue.pop();
    26.                 if (i == size - 1) {
    27.                     ans.push_back(tmp);
    28.                 }
    29.                 if (front->left) {
    30.                     queue.push(front->left);
    31.                 }
    32.                 if(front->right) {
    33.                     queue.push(front->right);
    34.                 }
    35.             }
    36.         }
    37.         return ans;
    38.     }
    39. };