237. Delete Node in a Linked List

Description

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

Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node with value 3, the linked list should become 1 -> 2 -> 4 after calling your function.

Solution

Swap & Delete, O(1), S(1)

啰嗦写法：

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public void deleteNode(ListNode node) {
        ListNode next = node.next;
        // swap values
        int tmp = node.val;
        node.val = next.val;
        next.val = tmp;
        // delete next
        node.next = next.next;
        next.next = null;
    }
}

精简写法：

class Solution {
    public void deleteNode(ListNode node) {
        node.val = node.next.val;
        node.next = node.next.next;
    }
}