Package g0101_0200.s0144_binary_tree_preorder_traversal

Class Solution

java.lang.Object
g0101_0200.s0144_binary_tree_preorder_traversal.Solution
public class Solution extends java.lang.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
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    java.util.List<java.lang.Integer>
    preorderTraversal(TreeNode root)
     

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • preorderTraversal

      public java.util.List<java.lang.Integer> preorderTraversal(TreeNode root)