Topic description
Each node of the binary tree is printed from top to bottom, and the nodes of the same level are printed from left to right.
/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Solution {
public:
vector<int> PrintFromTopToBottom(TreeNode* root) {
queue<TreeNode*>q;
vector<int>vt;
if(root == NULL)
return vt;
q.push(root);
vt.push_back(root->val);
while(!q.empty()){
TreeNode* tmp = q.front();
q.pop();
if(tmp->left != NULL){
vt.push_back(tmp->left->val);
q.push(tmp->left);
}
if(tmp->right != NULL){
vt.push_back(tmp->right->val);
q.push(tmp->right);
}
}
return vt;
}
};