Contents

237. Delete Node in a Linked List

Problem

Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.

example 1

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Input: head = [4,5,1,9], node = 5
Output: [4,1,9]
Explanation: You are given the second node with value 5, the linked list should become 4 -> 1 -> 9 after calling your function.

example 2

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Input: head = [4,5,1,9], node = 1
Output: [4,5,9]
Explanation: You are given the third node with value 1, the linked list should become 4 -> 5 -> 9 after calling your function.

Constraint

  • The linked list will have at least two elements.
  • All of the nodes’ values will be unique.
  • The given node will not be the tail and it will always be a valid node of the linked list.
  • Do not return anything from your function.

Solution

Unref

Unref current node and set value – next node,

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/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func deleteNode(node *ListNode) {
    if node == nil {
        return
    }
    
    if node.Next == nil {
        return
    }
    
    *node = *node.Next
}

Copy

Copy node.Next.Val and node.Next.Next to current node

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/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func deleteNode(node *ListNode) {
    if node == nil {
        return
    }
    
    if node.Next == nil {
        return
    }
    
    node.Val = node.Next.Val
    node.Next = node.Next.Next   
}