g0101_0200.s0144_binary_tree_preorder_traversal

Class Solution

java.lang.Object

g0101_0200.s0144_binary_tree_preorder_traversal.Solution

public class Solution
extends Object

144 - Binary Tree Preorder Traversal.

Easy

Given the root of a binary tree, return the preorder traversal of its nodes’ values.

Example 1:

Input: root = [1,null,2,3]

Output: [1,2,3]

Example 2:

Input: root = []

Output: []

Example 3:

Input: root = [1]

Output: [1]

Example 4:

Input: root = [1,2]

Output: [1,2]

Example 5:

Input: root = [1,null,2]

Output: [1,2]

Constraints:

• The number of nodes in the tree is in the range [0, 100].
• -100 <= Node.val <= 100

Follow up: Recursive solution is trivial, could you do it iteratively?

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
List<Integer>	preorderTraversal(TreeNode root)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

preorderTraversal

public List<Integer> preorderTraversal(TreeNode root)