剑指Offer——从上往下打印二叉树

 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 class Solution {
11 public:
12     vector<int> PrintFromTopToBottom(TreeNode* root) {
13         vector<int> res;
14         if(root == NULL) return res;
15         queue<TreeNode*> myQueue;
16         myQueue.push(root);
17         while(!myQueue.empty()) {
18             TreeNode* top = myQueue.front();
19             myQueue.pop();
20             res.push_back(top->val);
21             if(top->left != NULL) myQueue.push(top->left);
22             if(top->right != NULL) myQueue.push(top->right);
23         }
24         return res;
25     }
26 };