Merge pull request #171 from fartem/remove-nodes-from-linked-list

2023-01-22 update: added "2487. Remove Nodes From Linked List"

Author: fartem

README.md

@@ -744,6 +744,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 2375. Construct Smallest Number From DI String                                      | [Link](https://leetcode.com/problems/construct-smallest-number-from-di-string/)                                      | [Link](./src/main/java/com/smlnskgmail/jaman/leetcodejava/medium/ConstructSmallestNumberFromDIString.java)                             |
 | 2390. Removing Stars From a String                                                  | [Link](https://leetcode.com/problems/removing-stars-from-a-string/)                                                  | [Link](./src/main/java/com/smlnskgmail/jaman/leetcodejava/medium/RemovingStarsFromAString.java)                                        |
 | 2415. Reverse Odd Levels of Binary Tree                                             | [Link](https://leetcode.com/problems/reverse-odd-levels-of-binary-tree/)                                             | [Link](./src/main/java/com/smlnskgmail/jaman/leetcodejava/medium/ReverseOddLevelsOfBinaryTree.java)                                    |
+| 2487. Remove Nodes From Linked List                                                 | [Link](https://leetcode.com/problems/remove-nodes-from-linked-list/)                                                 | [Link](./src/main/java/com/smlnskgmail/jaman/leetcodejava/medium/RemoveNodesFromLinkedList.java)                                       |
 
 ### Hard
 

src/main/java/com/smlnskgmail/jaman/leetcodejava/medium/RemoveNodesFromLinkedList.java

@@ -0,0 +1,26 @@
+package com.smlnskgmail.jaman.leetcodejava.medium;
+
+import com.smlnskgmail.jaman.leetcodejava.support.ListNode;
+
+// https://leetcode.com/problems/remove-nodes-from-linked-list/
+public class RemoveNodesFromLinkedList {
+
+    private final ListNode input;
+
+    public RemoveNodesFromLinkedList(ListNode input) {
+        this.input = input;
+    }
+
+    public ListNode solution() {
+        return removeNodes(input);
+    }
+
+    private ListNode removeNodes(ListNode head) {
+        if (head == null) {
+            return null;
+        }
+        head.next = removeNodes(head.next);
+        return head.next != null && head.val < head.next.val ? head.next : head;
+    }
+
+}

src/test/java/com/smlnskgmail/jaman/leetcodejava/medium/RemoveNodesFromLinkedListTest.java

@@ -0,0 +1,30 @@
+package com.smlnskgmail.jaman.leetcodejava.medium;
+
+import com.smlnskgmail.jaman.leetcodejava.support.ListNode;
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+
+public class RemoveNodesFromLinkedListTest {
+
+    @Test
+    public void defaultTests() {
+        assertTrue(
+                ListNode.areEqual(
+                        ListNode.fromNumbers(13, 8),
+                        new RemoveNodesFromLinkedList(
+                                ListNode.fromNumbers(5, 2, 13, 3, 8)
+                        ).solution()
+                )
+        );
+        assertTrue(
+                ListNode.areEqual(
+                        ListNode.fromNumbers(1, 1, 1, 1),
+                        new RemoveNodesFromLinkedList(
+                                ListNode.fromNumbers(1, 1, 1, 1)
+                        ).solution()
+                )
+        );
+    }
+
+}