* Definition for a binary tree node.
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
vector<double> averageOfLevels(TreeNode* root) {
deque<TreeNode*> tree(1,root);
if(tree[0]->left) tree.push_back(tree[0]->left);
if(tree[0]->right) tree.push_back(tree[0]->right);