# Is the test case of this problem very small?

• I get accepted by using the following buggy solution, but the same solution can't pass the Problem Binary Tree Level Order Traversal II.

``````class Solution {
public:
vector<vector<int> > levelOrder(TreeNode *root) {
//@ret: answer we will return
vector<vector<int> > ret;
//travel the tree and calculate the answer
process(root, 1, ret);
return ret;
}
//return the level of x
//@x: the index of the node (>=1)
int log2(int x)
{
int ret = 0;
while((1<<ret) <= x)
++ret;
return ret-1;
}
//travel the tree
void process(TreeNode *cur, int key, vector<vector<int> > &ret)
{
//the tree is empty
if(NULL == cur)
return;
//get the index of current node
int idx = log2(key);
//push a new level into the ret if needed
if(idx>=ret.size())
ret.push_back(vector<int>());
ret[idx].push_back(cur->val);
//process the left subtree
//!!!!!!!!!!!be careful!!!!!!!
//key*2 will be very large!!!!!!!!!
//!!!!!may not in the range of int!!!!!!!!!!!!!!
process(cur->left, key*2, ret);
//process the right subtree
process(cur->right, key*2+1, ret);
}
};``````

• What is the question? If this is about "Binary Tree Level Order Traversal II", please post a question there and explain in plain text how you solve "Binary Tree Level Order Traversal", how you're trying to solve "Binary Tree Level Order Traversal II", why you think it doesn't work, etc.

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