问递归列表-计算所有元素的总和，包括最后一次出现的元素

EN

public class RecursiveList {
    static Node head;
    static boolean found = false;

    public static void main(String[] args) {
        RecursiveList list = new RecursiveList();

        list.addNumber(3);
        list.addNumber(5);
        list.addNumber(2);
        list.addNumber(7);
        list.addNumber(5);
        list.addNumber(1);
        list.addNumber(4);
        list.printList();

        int result = list.sumLastOcc(head, 5);

        System.out.println();
        System.out.println(result);
    }

    private int sumLastOcc(Node n, int val) {
        // CODE TO IMPLEMENT    
        }

        return sum;
    }

    private void addNumber(int number) {
        Node curr = head;
        Node prev = null;

        if (head == null) {
            head = new Node(number, null);
        } else {
            while (curr != null) {
                prev = curr;
                curr = curr.next;
            }

            Node newNode = new Node(number, null);
            prev.next = newNode;
        }
    }

    // inner node class
    private class Node {
        Node next;
        int value;

        Node(int value, Node next) {
            this.value = value;
            this.next = next;
        }
    }

    private void printList() {
        Node curr = head;
        Node prev = null;

        while (curr != null) {
            System.out.print(curr.value + " ");

            prev = curr;
            curr = curr.next;
        }
    }
}