---
description: 'Author: @TBC | https://leetcode.com/problems/merge-nodes-in-between-zeros/'
draft: 'true'
---

# 2181 - Merge Nodes in Between Zeros (Medium)

## Problem Link

https://leetcode.com/problems/merge-nodes-in-between-zeros/

## Problem Statement

You are given the `head` of a linked list, which contains a series of integers **separated** by `0`'s. The **beginning** and **end** of the linked list will have `Node.val == 0`.

For **every** two consecutive `0`'s, **merge** all the nodes lying in between them into a single node whose value is the **sum** of all the merged nodes. The modified list should not contain any `0`'s.

Return _the_ `head` _of the modified linked list_.

**Example 1:**

![](https://assets.leetcode.com/uploads/2022/02/02/ex1-1.png)

```
Input: head = [0,3,1,0,4,5,2,0]
Output: [4,11]
Explanation: 
The above figure represents the given linked list. The modified list contains
- The sum of the nodes marked in green: 3 + 1 = 4.
- The sum of the nodes marked in red: 4 + 5 + 2 = 11.
```

**Example 2:**

![](https://assets.leetcode.com/uploads/2022/02/02/ex2-1.png)

```
Input: head = [0,1,0,3,0,2,2,0]
Output: [1,3,4]
Explanation: 
The above figure represents the given linked list. The modified list contains
- The sum of the nodes marked in green: 1 = 1.
- The sum of the nodes marked in red: 3 = 3.
- The sum of the nodes marked in yellow: 2 + 2 = 4.
```

**Constraints:**

* The number of nodes in the list is in the range `[3, 2 * 10^5]`.
* `0 <= Node.val <= 1000`
* There are **no** two consecutive nodes with `Node.val == 0`.
* The **beginning** and **end** of the linked list have `Node.val == 0`.

## Approach 1: TBC
