Given a non-negative integer represented as a linked list of digits, plus one to the integer.
The digits are stored such that the most significant digit is at the head
of the list.
Example 1:
Input: head = [1,2,3] Output: [1,2,4]
Example 2:
Input: head = [0] Output: [1]
Constraints:
- The number of nodes in the linked list is in the range
[1, 100]
. 0 <= Node.val <= 9
- The number represented by the linked list does not contain leading zeros except for the zero itself.
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next = next
class Solution:
def plusOne(self, head: ListNode) -> ListNode:
dummy = ListNode(val=0, next=head)
target = dummy
while head:
if head.val != 9:
target = head
head = head.next
target.val += 1
target = target.next
while target:
target.val = 0
target = target.next
return dummy if dummy.val else dummy.next
/**
* 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 ListNode plusOne(ListNode head) {
ListNode dummy = new ListNode(0, head);
ListNode target = dummy;
while (head != null) {
if (head.val != 9) {
target = head;
}
head = head.next;
}
target.val += 1;
target = target.next;
while (target != null) {
target.val = 0;
target = target.next;
}
return dummy.val == 1 ? dummy : dummy.next;
}
}