Easy
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
Constraints:
30
.0
or 1
.import com_github_leetcode.ListNode;
/*
* 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; }
* }
*/
public class Solution {
public int getDecimalValue(ListNode head) {
int l = 0;
ListNode curr = head;
while (curr.next != null) {
l++;
curr = curr.next;
}
curr = head;
int num = 0;
while (curr != null) {
num += curr.val * (int) Math.pow(2, l--);
curr = curr.next;
}
return num;
}
}