Given a binary tree, return the inorder traversal of its nodes' values.
For example:
Given binary tree [1,null,2,3]
,
1 \ 2 / 3
return [1,3,2]
.
Note: Recursive solution is trivial, could you do it iteratively?
Answers:
class Solution { public: vector<int> inorderTraversal(TreeNode* root) { std::vector<int> ans; inorderTraversal(root,ans); return ans; } void inorderTraversal(TreeNode* root, std::vector<int>& ans) { if(!root) return; if(root->left!=NULL){ inorderTraversal(root->left,ans); } ans.push_back(root->val); if(root->right!=NULL){ inorderTraversal(root->right,ans); } } };