leetcode设计链表

Question

自己写的设计链表测试过了，但是执行出错，麻烦看一下哪错了，谢谢

class ListNode{
    int val;
    ListNode next;
    ListNode(){}
    ListNode(int val){this.val = val;}
    ListNode(int val,ListNode next){this.val = val;this.next = next;}
}

class MyLinkedList {
    ListNode head;
    public MyLinkedList() {
        //定义虚拟头节点
        this.head = new ListNode(0);
    }
    
    public int get(int index) {
        ListNode cur = head;
        while(index != 0){
            cur = cur.next;
            index--;
        }
        return cur.next.val;
    }
    
    public void addAtHead(int val) {
        ListNode newNode = new ListNode(val);
        newNode.next = head.next;
        head.next = newNode;
    }
    
    public void addAtTail(int val) {
        ListNode cur = head;
        ListNode newNode = new ListNode(val);
        while(cur.next != null){
            cur = cur.next;
            
        }
        cur.next = newNode;
    }
    
    public void addAtIndex(int index, int val) {
        ListNode cur = head;
        ListNode newNode = new ListNode(val);
        while(index != 0){
            cur = cur.next;
            index--;
        }
        newNode.next = cur.next;
        cur.next = newNode;
        
    }
    
    public void deleteAtIndex(int index) {
        ListNode cur = head;
        while(index != 0){
            cur = cur.next;
            index--;
        }
        cur.next = cur.next.next;
    }
}

/**
 * Your MyLinkedList object will be instantiated and called as such:
 * MyLinkedList obj = new MyLinkedList();
 * int param_1 = obj.get(index);
 * obj.addAtHead(val);
 * obj.addAtTail(val);
 * obj.addAtIndex(index,val);
 * obj.deleteAtIndex(index);
 */

Answer 1

你的 get() 方法要注意判断 index 是否超出列表范围。addAtIndex() 和 deleteAtIndex() 也需要注意。