Leetcode: 1290
1290. 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
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.
Solution:
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
class Solution {
public int getDecimalValue(ListNode head) {
int count = 0;
while(head != null){
count = count * 2 + head.val;
//count = (count << 1) + head.val; don't miss (), because of the priority
head = head.next;
}
return count;
}
}