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.
* public class ListNode {
* public int val;
* public ListNode next;
* public ListNode(int val=0, ListNode next=null) {
* this.val = val;
* this.next = next;
* }
* }
*/
public class Solution {
public int GetDecimalValue(ListNode head) {
int len=0;
ListNode temp = head;
while(temp!=null){
len++;
temp = temp.next;
}
int res = 0;
while(head!=null){
if(head.val==1){
res+=(int)Math.Pow(2,len-1);
}
head = head.next;
len--;
}
return res;
}
}Time Complexity: O(n)
Space Complexity: O(1)
