add 2487

Author: fishercoder1534

Diff for: paginated_contents/algorithms/3rd_thousand/README.md

@@ -43,6 +43,7 @@
 | 2506 | [Count Pairs Of Similar Strings](https://leetcode.com/problems/count-pairs-of-similar-strings/)                                               | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2506.java)                                       || Easy                                 ||
 | 2496 | [Maximum Value of a String in an Array](https://leetcode.com/problems/maximum-value-of-a-string-in-an-array/)                                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2496.java)                                       || Easy                                 ||
 | 2492 | [Minimum Score of a Path Between Two Cities](https://leetcode.com/problems/minimum-score-of-a-path-between-two-cities/)                                                                                                             | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2492.java)                                       || Medium                               | Union Find                
+| 2487 | [Remove Nodes From Linked List](https://leetcode.com/problems/remove-nodes-from-linked-list/)                                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2487.java)                                       || Medium                               |LinkedList, Stack
 | 2485 | [Find the Pivot Integer](https://leetcode.com/problems/find-the-pivot-integer/)                                                                                 | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2485.java)                                       || Easy                                 ||
 | 2467 | [Convert the Temperature](https://leetcode.com/problems/convert-the-temperature/)                                                                                                             | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2469.java)                                       || Easy                                 ||
 | 2455 | [Average Value of Even Numbers That Are Divisible by Three](https://leetcode.com/problems/average-value-of-even-numbers-that-are-divisible-by-three/)                                         | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/thirdthousand/_2455.java)                                       || Easy                                 ||

Diff for: src/main/java/com/fishercoder/solutions/thirdthousand/_2487.java

@@ -0,0 +1,54 @@
+package com.fishercoder.solutions.thirdthousand;
+
+import com.fishercoder.common.classes.ListNode;
+
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
+
+public class _2487 {
+    public static class Solution1 {
+        /**
+         * This is sort of cheating, i.e. transforming the linked list into an array instead of operating on the linked list itself.
+         */
+        public ListNode removeNodes(ListNode head) {
+            List<Integer> list = getList(head);
+            Deque<Integer> rightBiggest = getRightBiggest(list);
+            ListNode pre = new ListNode(-1);
+            ListNode tmp = pre;
+            for (int i = 0; i < list.size(); i++) {
+                if (list.get(i) >= rightBiggest.pollFirst()) {
+                    tmp.next = new ListNode(list.get(i));
+                    tmp = tmp.next;
+                }
+            }
+            return pre.next;
+        }
+
+        private Deque<Integer> getRightBiggest(List<Integer> list) {
+            Deque<Integer> result = new LinkedList<>();
+            int max = list.get(list.size() - 1);
+            result.addFirst(max);
+            for (int i = list.size() - 2; i >= 0; i--) {
+                max = Math.max(max, list.get(i));
+                result.addFirst(max);
+            }
+            return result;
+        }
+
+        private List<Integer> getList(ListNode head) {
+            ListNode tmp = head;
+            List<Integer> list = new ArrayList<>();
+            while (tmp != null) {
+                list.add(tmp.val);
+                tmp = tmp.next;
+            }
+            return list;
+        }
+    }
+
+    public static class Solution2 {
+        //TODO: use stack to solve this problem
+    }
+}

Diff for: src/test/java/com/fishercoder/thirdthousand/_2487Test.java

@@ -0,0 +1,30 @@
+package com.fishercoder.thirdthousand;
+
+import com.fishercoder.common.utils.LinkedListUtils;
+import com.fishercoder.solutions.thirdthousand._2487;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class _2487Test {
+    private static _2487.Solution1 solution1;
+
+    @BeforeEach
+    public void setup() {
+        solution1 = new _2487.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(LinkedListUtils.contructLinkedList(new int[]{13, 8}), solution1.removeNodes(LinkedListUtils.contructLinkedList(new int[]{5, 2, 13, 3, 8})));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals(LinkedListUtils.contructLinkedList(new int[]{998, 961, 943, 920, 698}),
+                solution1.removeNodes(LinkedListUtils.contructLinkedList(
+                        new int[]{138, 466, 216, 67, 642, 978, 264, 136, 463, 331, 60, 600, 223, 275, 856, 809, 167, 101, 846, 165, 575, 276, 409, 590, 733, 200, 839, 515, 852, 615, 8, 584, 250, 337, 537, 63, 797, 900, 670, 636, 112, 701, 334, 422, 780, 552, 912, 506, 313, 474, 183, 792, 822, 661, 37, 164, 601, 271, 902, 792, 501, 184, 559, 140, 506, 94, 161, 167, 622, 288, 457, 953, 700, 464, 785, 203, 729, 725, 422, 76, 191, 195, 157, 854, 730, 577, 503, 401, 517, 692, 42, 135, 823, 883, 255, 111, 334, 365, 513, 338, 65, 600, 926, 607, 193, 763, 366, 674, 145, 229, 700, 11, 984, 36, 185, 475, 204, 604, 191, 898, 876, 762, 654, 770, 774, 575, 276, 165, 610, 649, 235, 749, 440, 607, 962, 747, 891, 943, 839, 403, 655, 22, 705, 416, 904, 765, 905, 574, 214, 471, 451, 774, 41, 365, 703, 895, 327, 879, 414, 821, 363, 30, 130, 14, 754, 41, 494, 548, 76, 825, 899, 499, 188, 982, 8, 890, 563, 438, 363, 32, 482, 623, 864, 161, 962, 678, 414, 659, 612, 332, 164, 580, 14, 633, 842, 969, 792, 777, 705, 436, 750, 501, 395, 342, 838, 493, 998, 112, 660, 961, 943, 721, 480, 522, 133, 129, 276, 362, 616, 52, 117, 300, 274, 862, 487, 715, 272, 232, 543, 275, 68, 144, 656, 623, 317, 63, 908, 565, 880, 12, 920, 467, 559, 91, 698})));
+    }
+
+}