Given the head node head of a singly linked list, where each node stores a binary digit, interpret the sequence of node values from head to the tail as a binary number and return its value in base $10$.

Note: The most significant bit is at head.

Constraints:

• The linked list is not empty.

• The number of nodes in the linked list does not exceed $30$.

• Each node’s value is either $0$ or $1$.

Input: head = [1]-ListNode
Output: 1-int
Explanation: The linked list represents the binary number 1, which equals 1 in base 10.

Input: head = [1, 1, 0, 1, 0]-ListNode
Output: 26-int
Explanation: The bits form 11010₂, which converts to decimal as 1·2⁴ + 1·2³ + 0·2² + 1·2¹ + 0·2⁰ = 16 + 8 + 0 + 2 + 0 = 26.

Input: head = [0, 0, 0, 1, 1]-ListNode
Output: 3-int
Explanation: The bits form 00011₂, which is 3 in decimal (2 + 1).

Input: head = [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]-ListNode
Output: 536870913-int
Explanation: This is a 30-bit number with 1 at the most significant position and 1 at the least significant position: 100000000000000000000000000001₂ = 2²⁹ + 2⁰ = 536870912 + 1 = 536870913.

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