55. 刪除鏈表中重複的結點《劍指Offer》(Java版)

題目描述

在一個排序的鏈表中，存在重複的結點，請刪除該鏈表中重複的結點，重複的結點不保留，返回鏈表頭指針。 例如，鏈表1->2->3->3->4->4->5 處理後爲 1->2->5

 

/*
 public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}
*/
public class Solution {
     // 鏈表節點的刪除
    public ListNode deleteDuplication(ListNode pHead) {
        ListNode cur = pHead;
        ListNode pre = null;
        if (pHead == null) {
            return null;
        }
         while (cur != null) {
            while (cur != null && cur.next != null && cur.val == cur.next.val) {
                while (cur.next != null && cur.val == cur.next.val) {
                    cur = cur.next;
                }
                cur = cur.next;
            }
            if (pre == null) {
                pre = cur;
                pHead = cur;
            } else {
                pre.next = cur;
                pre = cur;
            }
            if(cur == null){
                break;
            }
            cur = cur.next;
        }
        return pHead;
    }
}