> For the complete documentation index, see [llms.txt](https://mayanktyagi3111.gitbook.io/interview-prep/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mayanktyagi3111.gitbook.io/interview-prep/linked-list/remove-zero-sum-consecutive-nodes-from-linked-list.md).

# Remove Zero Sum Consecutive Nodes from Linked List

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`.

```java
class Solution {
    public ListNode removeZeroSumSublists(ListNode head) {
        ListNode dummy = new ListNode(0), cur = dummy;
        dummy.next = head;
        int sum = 0;
        Map<Integer, ListNode> map = new HashMap<>();
        while (cur != null) {
            sum += cur.val;
            if (map.containsKey(sum)) {
                cur = map.get(sum).next;
                int p = sum + cur.val;
                // Removing all the prefix Sum values from this range
                while (p != sum) {
                    map.remove(p);
                    cur = cur.next;
                    p += cur.val;
                }
                map.get(sum).next = cur.next;
            } else
                map.put(sum, cur);
            cur = cur.next;
        }
        return dummy.next;
    }
}
```


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