Lintcode.66 Binary Tree forward traversal, lintcode.66 Binary Tree

Lintcode.66 Binary Tree forward traversal, lintcode.66 Binary Tree
Forward traversal of Binary Trees 

• Description
• Notes
• Data
• Evaluation

Returns a binary tree that traverses the node values in the forward order.

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Returns a binary tree.{1,#,2,3},

   1    \     2    /   3

Return[1,2,3].

 

 

/** * Definition of TreeNode: * class TreeNode { * public: *     int val; *     TreeNode *left, *right; *     TreeNode(int val) { *         this->val = val; *         this->left = this->right = NULL; *     } * } */class Solution {public:    /*     * @param root: A Tree     * @return: Preorder in ArrayList which contains node values.     */    vector<int> l;    vector<int> preorderTraversal(TreeNode * root) {        // write your code here        if(root==NULL)            return l;        l.push_back(root->val);        preorderTraversal(root->left);        preorderTraversal(root->right);        return l;    }};