題目82. Remove Duplicates from Sorted List II
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.
1
public class Solution {
public ListNode deleteDuplicates(ListNode head) {
if(head == null || head.next == null){
return head;
}
ListNode tempHead = new ListNode(1);
tempHead.next = head;
ListNode preHeadNode = tempHead;
int val = head.val;
int count = 1;
ListNode node = head.next;
while(node != null){
if(node.val == val){
count++;
}else{
if(count == 1){
preHeadNode = preHeadNode.next;
}else{
preHeadNode.next = node;
}
val = node.val;
count = 1;
}
node = node.next;
}
if(count != 1){
preHeadNode.next = null;
}
return tempHead.next;
}
}
