Program to find the K-th last node of a linked list in Python
Suppose we have a singly linked list, we have to check find the value of the kth last node (0-indexed). We have to solve this in single pass.
So, if the input is like node = [5,4,6,3,4,7], k = 2, then the output will be 3, as The second last (index 3) node has the value of 3.
To solve this, we will follow these steps −
klast := node
last := node
for i in range 0 to k, do
while next of last is not null, do
last := next of last
klast := next of klast
return value of klast
Let us see the following implementation to get better understanding −
Example
Live Demo
class ListNode:
def __init__(self, data, next = None):
self.val = data
self.next = next
def make_list(elements):
head = ListNode(elements[0])
for element in elements[1:]:
ptr = head
while ptr.next:
ptr = ptr.next
ptr.next = ListNode(element)
return head
class Solution:
def solve(self, node, k):
klast = node
last = node
for i in range(k):
last = last.next
while last.next:
last = last.next
klast = klast.next
return klast.val
ob = Solution()
l1 = make_list([5,4,6,3,4,7])
print(ob.solve(l1, 2))
Input
[5,4,6,3,4,7], 2
Output
3
Published on 09-Oct-2020 14:28:40
