Java单链表插入元素算法实现 - 在指定位置插入节点

public class ListNode {
    int val;
    ListNode next;

    ListNode(int val) {
        this.val = val;
    }
}

public class LinkedList {
    private ListNode head;

    public LinkedList() {
        head = null;
    }

    // 在第i个结点之前插入元素x
    public boolean insert(int i, int x) {
        if (i < 0 || i > getLength()) {
            return false;
        }

        ListNode newNode = new ListNode(x);
        if (i == 0) {
            newNode.next = head;
            head = newNode;
        } else {
            ListNode current = head;
            for (int j = 0; j < i - 1; j++) {
                current = current.next;
            }
            newNode.next = current.next;
            current.next = newNode;
        }

        return true;
    }

    // 获取链表长度
    public int getLength() {
        int length = 0;
        ListNode current = head;
        while (current != null) {
            length++;
            current = current.next;
        }
        return length;
    }

    // 打印链表
    public void printList() {
        ListNode current = head;
        while (current != null) {
            System.out.print(current.val + ' ' );
            current = current.next;
        }
        System.out.println();
    }

    public static void main(String[] args) {
        LinkedList list = new LinkedList();
        list.insert(0, 6);
        list.insert(1, 1);
        list.insert(2, 2);
        list.insert(3, 3);
        list.insert(4, 4);
        list.insert(5, 5);

        list.printList();  // 输出：6 1 2 3 4 5
    }
}