'''
Convert Binary Number in a Linked List to Integer
Easy

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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
Example 3:

Input: head = [1]
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
'''
class ListNode:
     def __init__(self, val=0, next=None):
         self.val = val
         self.next = next
class Solution:
    def getDecimalValue(self, head: ListNode) -> int:
        cur = head
        array = ''
        while cur:
            array += str(cur.val)
            cur = cur.next
        decimal = 0
        for digit in array:
            decimal = decimal*2 + int(digit)
        return decimal
