public class Solution
extends Object
1290 - Convert Binary Number in a Linked List to Integer\.
Easy
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 = [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`.