Formatted question description: https://leetcode.ca/all/1171.html

# 1171. Remove Zero Sum Consecutive Nodes from Linked List

## Level

Medium

## Description

Given the `head`

of a linked list, we repeatedly delete consecutive sequences of nodes that sum to `0`

until there are no such sequences.

After doing so, return the head of the final linked list. You may return any such answer.

(Note that in the examples below, all sequences are serializations of `ListNode`

objects.)

**Example 1:**

**Input:** head = [1,2,-3,3,1]

**Output:** [3,1]

**Note:** The answer [1,2,1] would also be accepted.

**Example 2:**

**Input:** head = [1,2,3,-3,4]

**Output:** [1,2,4]

**Example 3:**

**Input:** head = [1,2,3,-3,-2]

**Output:** [1]

**Constraints:**

- The given linked list will contain between
`1`

and`1000`

nodes. - Each node in the linked list has
`-1000 <= node.val <= 1000`

.

## Solution

Create a `dummyHead`

and set `dummyHead.next = head`

. Initialize `temp = dummyHead`

. Each time delete zero sum consecutive nodes starting from `temp.next`

. If there are nodes that are deleted, set `temp.next`

to be the next node after deletion. Otherwise, set `temp = temp.next`

.

Finally, return `dummyHead.next`

.

```
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
class Solution {
public ListNode removeZeroSumSublists(ListNode head) {
ListNode dummyHead = new ListNode(0);
dummyHead.next = head;
ListNode temp = dummyHead;
while (temp != null) {
ListNode zeroLast = removeZero(temp.next);
if (zeroLast == null)
temp = temp.next;
else
temp.next = zeroLast.next;
}
return dummyHead.next;
}
public ListNode removeZero(ListNode node) {
ListNode temp = node;
int sum = 0;
while (temp != null) {
sum += temp.val;
if (sum == 0)
return temp;
else
temp = temp.next;
}
return null;
}
}
```