Leetcode First brush _binary Tree level Order traversal II

Very easy title, at the back, I don't think it's so simple to answer more. We will write, no one.

Pre-order on the ground floor, plus save every layer, plus the output from the bottom up, is a vector and a stack so the problem, without him, but on the other hand-cooked Seoul.

Class Solution {public:vector<vector<int> > Levelorderbottom (TreeNode *root) {vector<vector<        int> > Res;        if (root = NULL) return res;        Queue<treenode*> que;        stack<vector<int> > S;        Vector<int> Tpres;        TreeNode *pnode;        Que.push (root);        Que.push (NULL);            while (!que.empty ()) {Pnode = Que.front ();            Que.pop ();                if (Pnode = = NULL) {s.push (tpres);                Tpres.clear ();                if (Que.empty ()) break;                    else{Que.push (NULL);                Continue            }} tpres.push_back (Pnode->val);            if (pnode->left) Que.push (pnode->left);        if (pnode->right) Que.push (pnode->right);            } while (!s.empty ()) {Res.push_back (S.top ());        S.pop (); } return Res; }};

Leetcode First brush _binary Tree level Order traversal II