Remove Nth Node From End Leetcode Solution
In this tutorial, we will solve a leetcode problem, remove Nth node from the end in python.
Task:
Given the head of a linked list, remove the nth node from the end of the list and return its head.
Example1:
Input: head = [1,2,3,4,5], n = 2
Output: [1,2,3,5]
Example2:
Input: head = [1], n = 1
Output: []
Example 3:
Input: head = [1,2], n = 1
Output: [1]
Constraints:
- The number of nodes in the list is sz.
- 1 <= sz <= 30
- 0 <= Node.val <= 100
- 1 <= n <= sz
Solution:
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next = next
class Solution:
def removeNthFromEnd(self, head: Optional[ListNode], n: int) -> Optional[ListNode]:
if head.next == None:
return None
count=0
cur = head
while cur:
count+=1
cur =cur.next
if count == 2 and n==1:
head.next =None
return head
elif count==2 and n==2:
head = head.next
return head
cur1 = head
if count-n == 0:
return head.next
for i in range(count-n):
if i == (count-n-1):
cur1.next = cur1.next.next
cur1 = cur1.next
return head
