'''
Author : MiKueen
Level : Easy
Problem Statement : Convert Binary Number in a Linked List to Integer

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

Constraints:
The Linked List is not empty.
Number of nodes will not exceed 30.
Each node's value is either 0 or 1.
'''

# 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:
        if head.next is None:
            return head.val
        
        # Method 1
        res = ''
        while head:
            res += str(head.val)
            head = head.next
        return int(res, 2)
    
        # Method 2 - Cool trick
        res = 0
        while head:
            res = 2 * res + head.val
            head = head.next
        return res
        
'''
Author : MiKueen
Level : Easy
Problem Statement : Convert Binary Number in a Linked List to Integer

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

Constraints:
The Linked List is not empty.
Number of nodes will not exceed 30.
Each node's value is either 0 or 1.
'''

# 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:
        if head.next is None:
            return head.val
        
        # Method 1
        res = ''
        while head:
            res += str(head.val)
            head = head.next
        return int(res, 2)
    
        # Method 2 - Cool trick
        res = 0
        while head:
            res = 2 * res + head.val
            head = head.next
        return res
        
Author : MiKueen Level : Easy Problem Statement : Convert Binary Number in a Linked List to Integer  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  Constraints: The Linked List is not empty. Number of nodes will not exceed 30. Each node's value is either 0 or 1. # Definition for singly-linked list. # class ListNode: #     def __init__(self, val=0, next=None): #         self.val = val #         self.next = next # Method 1 # Method 2 - Cool trick