LeetCode_237. Delete Node in a Linked List

237. Delete Node in a Linked List

Easy

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

Given linked list -- head = [4,5,1,9], which looks like following:

Example 1:

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:

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.

Note:

• 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.

package leetcode.easy;

/**
 * Definition for singly-linked list. public class ListNode { int val; ListNode
 * next; ListNode(int x) { val = x; } }
 */
public class DeleteNodeInALinkedList {
	private static void print(ListNode head) {
		if (head == null) {
			return;
		}
		while (head != null) {
			System.out.print(head.val);
			if (head.next != null) {
				System.out.print("->");
			}
			head = head.next;
		}
		System.out.println();
	}

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

	@org.junit.Test
	public void test1() {
		ListNode listNode1 = new ListNode(4);
		ListNode listNode2 = new ListNode(5);
		ListNode listNode3 = new ListNode(1);
		ListNode listNode4 = new ListNode(9);
		listNode1.next = listNode2;
		listNode2.next = listNode3;
		listNode3.next = listNode4;
		listNode4.next = null;
		print(listNode1);
		deleteNode(listNode2);
		print(listNode1);
	}

	@org.junit.Test
	public void test2() {
		ListNode listNode1 = new ListNode(4);
		ListNode listNode2 = new ListNode(5);
		ListNode listNode3 = new ListNode(1);
		ListNode listNode4 = new ListNode(9);
		listNode1.next = listNode2;
		listNode2.next = listNode3;
		listNode3.next = listNode4;
		listNode4.next = null;
		print(listNode1);
		deleteNode(listNode3);
		print(listNode1);
	}
}