Leetcode[tree]: Binary Tree level Order traversal II

Given a binary tree, return the bottom-up level order traversal of its nodes ' values. (ie, from the left-to-right, the level by level from the leaf to root).

This simple problem can be solved: using Leetcode[tree]: Binary Tree level order traversal the same method to get top-down sequence traversal results, the result is flipped. It can also be inserted without plugging from the tail and inserting from the head.

My C + + code is implemented as follows:

vector<vector<int> > Levelorderbottom (TreeNode *root) {    vector<vector<int> > result;    Vector<int> level;    Queue<treenode *> LEVELQ;    if (root) levelq.push (root);            while (!levelq.empty ()) {        level.clear ();        int size = Levelq.size ();        for (int i = 0; i < size; ++i) {            TreeNode *node = Levelq.front ();            Levelq.pop ();            Level.push_back (node->val);            if (node->left) Levelq.push (node->left);            if (node->right) Levelq.push (node->right);        }        Result.insert (Result.begin (), level);    }    return result;}

Leetcode[tree]: Binary Tree level Order traversal II