83. 删除排序链表中的重复元素

• 一、题目描述
• 二、示例
• 三、难度
• 四、代码
• • Java版

简单

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

public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        if (head == null) return null;
        // 快指针fast用来探路
        ListNode slow = head, fast = head.next;
        while (fast != null) {
            if (slow.val != fast.val) {
                slow.next = fast;
                slow = slow.next;
            }
            fast = fast.next;
        }
        // 断开与后面重复元素的连接
        slow.next = null;
        return head;
    }

    public static void main(String[] args) {
        ListNode node4 = new ListNode(3);
        ListNode node3 = new ListNode(3,node4);
        ListNode node2 = new ListNode(2,node3);
        ListNode node1 = new ListNode(1,node2);
        ListNode head = new ListNode(1,node1);
        ListNode list = new Solution().deleteDuplicates(head);

        while (list != null) {
            System.out.print(list.val+" ");
            list = list.next;
        }
    }
}