#include<vector>
#include<iostream>
#include<list>
using namespace std;

struct TreeNode
{
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

TreeNode* helper(vector<int>::iterator begin,vector<int>::iterator end)
{
    TreeNode *root=NULL;
    if(begin+1==end)
        return new TreeNode(*begin);
    if(begin>=end)
        return NULL;
    int mid=(end-begin-1)/2;
    root=new TreeNode(*(begin+mid));
    root->left=helper(begin,begin+mid);
    root->right=helper(begin+mid+1,end);
    return root;
}

TreeNode* createAVL(vector<int> &vec)
{
    if(vec.empty())
        return NULL;
    return helper(vec.begin(),vec.end());
}

vector<list<TreeNode*> > find_level_linklists(TreeNode *root)
{
    list<TreeNode*> ll;
    vector<list<TreeNode*> > ret;
    ll.push_back(root);
    ret.push_back(ll);
    while(!ll.empty())
    {
        list<TreeNode*> tmp=ll;
        ll.clear();
        auto iter=tmp.begin();
        while(iter!=tmp.end())
        {
            TreeNode *node=*iter;
            if(node->left)
                ll.push_back(node->left);
            if(node->right)
                ll.push_back(node->right);
            iter++;
        }
        if(!ll.empty())
            ret.push_back(ll);
    }
    return ret;
}

void print(vector<list<TreeNode*> > res)
{
    vector<list<TreeNode*> >::iterator vit;
    for(vit=res.begin(); vit!=res.end(); ++vit)
    {
        list<TreeNode*> li = *vit;
        list<TreeNode*>::iterator lit;
        for(lit=li.begin(); lit!=li.end(); ++lit)
        {
            TreeNode *n = *lit;
            cout<<n->val<<" ";
        }
        cout<<endl;
    }
}

int main()
{
    vector<int> vec= {1,2,3,4,5,6,7,8,9,10};
    TreeNode *root=createAVL(vec);
    vector<list<TreeNode*> > res=find_level_linklists(root);
    print(res);
}