# LeetCode 1290. Convert Binary Number in a Linked List to Integer

## Description

Given `head` which is a reference node to a singly-linked list. The value of each node in the linked list is either 0 or 1. The linked list holds the binary representation of a number.

Return the decimal value of the number in the linked list.

Example 1:

```Input: head = [1,0,1]
Output: 5
Explanation: (101) in base 2 = (5) in base 10
```

Example 2:

```Input: head = 
Output: 0
```

Example 3:

```Input: head = 
Output: 1
```

Example 4:

```Input: head = [1,0,0,1,0,0,1,1,1,0,0,0,0,0,0]
Output: 18880
```

Example 5:

```Input: head = [0,0]
Output: 0
```

Constraints:

• The Linked List is not empty.
• Number of nodes will not exceed `30`.
• Each node’s value is either `0` or `1`.

## Explanation

Multiply result by 2.

## Python Solution

``````# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
def getDecimalValue(self, head: ListNode) -> int:
result = 0