Please design a class which represents a node of binary tree, and write a function r preorder to traverse the binary tree from the root node in order by java.
时间: 2023-03-26 16:02:03 浏览: 92
好的,我可以回答这个问题。以下是一个表示二叉树节点的类的示例代码:
```
public class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) { val = x; }
}
```
以下是一个使用递归实现前序遍历的示例代码:
```
public void preorderTraversal(TreeNode root) {
if (root == null) {
return;
}
System.out.print(root.val + " ");
preorderTraversal(root.left);
preorderTraversal(root.right);
}
```
希望这个回答能够帮到你。
相关问题
Draw a binary tree with seven vertices and only one leaf.
Here is a possible binary tree with seven vertices and only one leaf:
```
o
/ \
o o
/ / \
o o o
/
o
```
Note that "o" represents a vertex and the leaf is the bottom-left vertex.
I want to delete the files which are created earlier than a particular time in a directory. How can I do this in shell scripts?
In shell scripts, you can use the `find` command along with the `-mtime` option to identify files created earlier than a specific time. Here's an example script that deletes files older than a certain number of days:
```shell
#!/bin/bash
directory="/path/to/directory"
days=7
# Find files older than the specified number of days and delete them
find "$directory" -type f -mtime +"$days" -exec rm {} \;
```
In this script, replace `/path/to/directory` with the actual directory path you want to search in. The `days` variable represents the number of days ago from which you want to delete files. Adjust it according to your needs.
The `find` command searches for files (`-type f`) in the specified directory and its subdirectories, which were modified more than `$days` days ago (`-mtime +"$days"`). The `-exec` option is used to execute the `rm` command on each found file (`{}` represents the file path) to delete it.
Please exercise caution while running scripts that involve file deletion, as it can permanently remove data. It's recommended to test the script on a small set of files or take appropriate backup measures before using it in production.