<p>Given the <code>head</code> of a linked list, we repeatedly delete consecutive sequences of nodes that sum to <code>0</code> until there are no such sequences.</p>

<p>After doing so, return the head of the final linked list.&nbsp; You may return any such answer.</p>

<p>&nbsp;</p>
<p>(Note that in the examples below, all sequences are serializations of <code>ListNode</code> objects.)</p>

<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> head = [1,2,-3,3,1]
<strong>Output:</strong> [3,1]
<strong>Note:</strong> The answer [1,2,1] would also be accepted.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> head = [1,2,3,-3,4]
<strong>Output:</strong> [1,2,4]
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> head = [1,2,3,-3,-2]
<strong>Output:</strong> [1]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The given linked list will contain between <code>1</code> and <code>1000</code> nodes.</li>
	<li>Each node in the linked list has <code>-1000 &lt;= node.val &lt;= 1000</code>.</li>
</ul>

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def removeZeroSumSublists(self, head: Optional[ListNode]) -> Optional[ListNode]:
        prefix = {}
        dummy = ListNode(val=0, next=head)
        curr = dummy
        curr_sum = 0
        while curr:
            curr_sum += curr.val
            if curr_sum in prefix:
                prev = prefix[curr_sum]
                curr = prev.next
                prefix_sum = curr_sum + curr.val
                while prefix_sum != curr_sum:
                    del prefix[prefix_sum]
                    curr = curr.next
                    prefix_sum += curr.val
                prev.next = curr.next
            else:
                prefix[curr_sum] = curr
            curr = curr.next
        return dummy.next
        

"""
[1, 2, -3, 3, 1]
[1, 3, 0, 3, 1]

[1,2,3,-3,4]
[1,3,6,3,7]

[1,2,3,-3,-2]
[1,3,6,3,1]

[1,3,2,-3,-2,5, 5,-5,1]
[1,4,6, 3, 1,6,11, 6,1]
"""
16500