Given a binary tree, return the preorder traversal of its nodes' values.
For example:
Given binary tree {1,#,2,3},
1 \ 2 / 3
return
[1,2,3].【LeetCode OJ - Binary Tree Preorder Traversal】 Note: Recursive solution is trivial, could you do it iteratively?
递归代码
/**
* Definition for binary tree
* struct TreeNode {
*int val;
*TreeNode *left;
*TreeNode *right;
*TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector preorderTraversal(TreeNode *root) {
vector rslt;
preorder(root, rslt);
return rslt;
}void preorder(TreeNode *root, vector &rslt) {
if(root) {
rslt.push_back(root->val);
preorder(root->left, rslt);
preorder(root->right, rslt);
}
}
};
