首页 > 代码库 > Binary Tree Preorder Traversal

Binary Tree Preorder Traversal

Binary Tree Preorder Traversal

 

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].

 1 /** 2  * Definition for binary tree 3  * public class TreeNode { 4  *     int val; 5  *     TreeNode left; 6  *     TreeNode right; 7  *     TreeNode(int x) { val = x; } 8  * } 9  */10 public class Solution {11     List<Integer> result = new ArrayList<Integer>();12     public List<Integer> preorderTraversal(TreeNode root) {13         if(null == root)14             return result;15         else{16             result.add(new Integer(root.val));17             preorderTraversal(root.left);18             preorderTraversal(root.right);19             return result;20         }21     }22 }

 

Binary Tree Preorder Traversal