Binary Tree level Order traversal I II

Binary Tree level Order traversal

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

For example:
Given binary Tree {3,9,20,#,#,15,7} ,

    3   /   9    /   7

Return its level order traversal as:

[  3],  [9,20],  [15,7]]

Ideas:

These two topics are very basic, BFS search.

Exercises

/** Definition for binary tree * struct TreeNode {* int val; * TreeNode *left; * TreeNode *right; * T Reenode (int x): Val (x), left (null), right (NULL) {} *}; */classSolution { Public: Vector<vector<int> > Levelorder (TreeNode *root) {Vector<vector<int> >Res; Vector<int>tmp; Queue<treenode *>Q; intCount =0, num =1; if(root==NULL)returnRes;        Q.push (root);  while(!Q.empty ()) {             for(intI=0; i<num;i++) {root=Q.front ();                Q.pop (); Tmp.push_back (Root-val); if(root->Left ) {Count++; Q.push (Root-Left ); }                if(root->Right ) {Count++; Q.push (Root-Right );            }} res.push_back (TMP); Num=count; Count=0;        Tmp.clear (); }        returnRes; }};

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).

For example:
Given binary Tree {3,9,20,#,#,15,7} ,

    3   /   9    /   7

Return its bottom-up level order traversal as:

[  [15,7],  [9,20],  [3]]
Exercises

/** Definition for binary tree * struct TreeNode {* int val; * TreeNode *left; * TreeNode *right; * T Reenode (int x): Val (x), left (null), right (NULL) {} *}; */classSolution { Public: Vector<vector<int> > Levelorderbottom (TreeNode *root) {Vector<vector<int> >Res; Vector<int>tmp; Queue<treenode *>Q; intCount =0, num =1; if(root==NULL)returnRes;        Q.push (root);  while(!Q.empty ()) {             for(intI=0; i<num;i++) {root=Q.front ();                Q.pop (); Tmp.push_back (Root-val); if(root->Left ) {Count++; Q.push (Root-Left ); }                if(root->Right ) {Count++; Q.push (Root-Right );            }} res.push_back (TMP); Num=count; Count=0;        Tmp.clear ();        } reverse (Res.begin (), Res.end ()); returnRes; }};

Binary Tree level Order traversal I II