在java中从preOrder和inOrder构建二叉树

Question

我有一个问题，这段代码，我在许多网站搜索，但我没有得到我想要的答案。我从GeeksforGeeks复制了这段代码，但我不知道问题出在哪里。我在linux等其他平台上测试了这段代码，但它不能在那里工作，我还在eclipse IDE上测试了它，它在那里不能工作，这是我的代码：

class SolveBT<E>  {

Node<E> treeRoot;
int preIndex = 0;

public SolveBT() {
    treeRoot = new Node<>(null);
}
 public void buildTree(E[] preOrder, E[] inOrder) {
     treeRoot = makeTree(preOrder, inOrder, 0, inOrder.length - 1);

}

private Node<E> makeTree(E[] preOrder, E[] inOrder, int start, int end) {
    if (start > end)
        return null;


    Node<E> node = new Node<>(preOrder[preIndex++]);

    if (start == end)
        return node;


    int index = find(inOrder, start, end, node.getData());


    node.setLeft(makeTree(inOrder, preOrder, start, index - 1));
    node.setRight(makeTree(inOrder, preOrder, index + 1, end));

    return node;
}

public int find(E[] arr, int start, int end, E value) {
    int i;
    for (i = start; i <end; i++) {
        if (arr[i] == value)
            return i;
    }
    return i;

}

}

   public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    SolveBT<String> tree = new SolveBT<>();


    String[] preOrder = scanner.nextLine().trim().split(" ");
    String[] inOrder = scanner.nextLine().trim().split(" ");


    tree.buildTree(preOrder, inOrder);


   AND THIS IS INPUT AND EXCEPTION :


   A B D E C F
   D B E A F C
    Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 
    6 out of bounds for length 6
at SolveBT.makeTree(ForStudents.java:290)
at SolveBT.makeTree(ForStudents.java:299)
at SolveBT.makeTree(ForStudents.java:299)
at SolveBT.makeTree(ForStudents.java:299)
at SolveBT.makeTree(ForStudents.java:299)
at SolveBT.makeTree(ForStudents.java:299)
at SolveBT.makeTree(ForStudents.java:299)
at SolveBT.buildTree(ForStudents.java:281)
at ForStudents.main(ForStudents.java:15)

Answer 1

错误出在行中

 Node<E> node = new Node<>(preOrder[preIndex++]);

每次调用函数时，preIndexvariable都会递增。检查它的用法和逻辑。根据我的观点，它应该是静态。