Remove Element from the single linked list

February 1, 2023

Name: Moch Lutfi
Twitter: @kaptenupi

Problem

Given a singly linked list of integers l and an integer k, remove all elements from list l that have a value equal to k.

Example

For l = [3, 1, 2, 3, 4, 5] and k = 3, the output should be
solution(l, k) = [1, 2, 4, 5];
For l = [1, 2, 3, 4, 5, 6, 7] and k = 10, the output should be
solution(l, k) = [1, 2, 3, 4, 5, 6, 7].

Note: Try to solve this task in O(n) time using O(1) additional space, where n is the number of elements in the list, since this is what you'll be asked to do during an interview.

Solution

The solution is straight forward, iterate linked list if cursor value equals with k skip cursor value by using prev.Next = cursor.Next

Talk is cheap, I show you the code. lol

create head that contains *ListNode and store head on the prev, because we cannot get previous ListNode from current Node
Iterate linked-list using help cursor
If current cursor value equals with k then delete current cursor by skipping current node
Otherwise update prev with current cursor
Return head.next

solution.go

// Singly-linked lists are already defined with this interface:
// type ListNode struct {
//   Value interface{}
//   Next *ListNode
// }
//
func solution(l *ListNode, k int) *ListNode {
    head:=&ListNode{Next:l}
    prev:= head
    
    for cursor:=l;cursor!=nil;cursor=cursor.Next{
        if cursor.Value.(int) == k {
            prev.Next = cursor.Next
        }else{
            prev = cursor
        }
    }
    
    return head.Next
}

Single linked list palindrome Check 2 strings are following patterns