import java.util.*;
public class Main {
/**
//该段代码仅用于调试,提交时请注释该段代码
class TreeNode<T> {
public T data;
public TreeNode<T> left;
public TreeNode<T> right;
}
*/
public Integer[] solution(TreeNode<Integer> data) {
List<Integer> result = new ArrayList<>();
solution(data, result);
return result.toArray(new Integer[result.size()]);
}
void solution(TreeNode<Integer> data, List<Integer> result) {
if (data == null) {
return;
}
solution(data.left, result);
result.add(data.data);
solution(data.right, result);
}
}