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.

The most significant bit is at the head of the linked list.

LeetCode Problem - 1290

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */

class Solution {
    public int getDecimalValue(ListNode head) {
        // Create a temporary pointer to traverse the linked list
        ListNode tempHead = head;
        // Initialize a StringBuilder to store the binary number as a string
        StringBuilder sb = new StringBuilder();

        // Traverse the linked list
        while (tempHead != null) {
            // Append the value of each node to the StringBuilder
            sb.append(tempHead.val);
            // Move to the next node in the list
            tempHead = tempHead.next;
        }

        // Convert the binary string to a decimal integer
        return Integer.parseInt(sb.toString(), 2);
    }
}