#include <iostream>
#include <vector>
#include <deque>
#include <algorithm>
using namespace std;

#define REP(i,n) for(int i=0;i<(n);++i)
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)

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

class Solution {
public:
    vector<vector<int> > levelOrderBottom(TreeNode *root) {
        vector<vector<int> > res;
        if (root == NULL) return res;
        deque<pair<TreeNode, int> > mm;
        mm.push_back(make_pair(*root, 0));
        while (!mm.empty()) {
            TreeNode now = mm.front().first;
            int idx = mm.front().second;
            mm.pop_front();
            if (res.size() <= idx) res.push_back(vector<int>());
            res[idx].push_back(now.val);
            if (now.left != NULL) mm.push_back(make_pair(*now.left, idx + 1));
            if (now.right != NULL) mm.push_back(make_pair(*now.right, idx + 1));
        }
        reverse(res.begin(), res.end());
        return res;
    }
};

int main() {
    return 0;
}