From b304f9f72a357e20485bb2a62f3f7839e54300dc Mon Sep 17 00:00:00 2001
From: Rishavbhattarai <bhattarai.rishav@gmail.com>
Date: Mon, 26 Oct 2026 19:27:13 -0700
Subject: [PATCH] fix(lists): leave SkipList size unchanged when removing a
 missing element

---
 .../datastructures/lists/SkipList.java             |  3 +++
 .../datastructures/lists/SkipListTest.java         | 14 ++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
index 0b4fcd91483c..7e03ca3856b5 100644
--- a/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
+++ b/src/main/java/com/thealgorithms/datastructures/lists/SkipList.java
@@ -121,6 +121,9 @@ public void remove(E e) {
                 current = next;
             }
         }
+        if (layer < 0) {
+            return; // not found, nothing to unlink
+        }
         for (int i = 0; i <= layer; i++) {
             current.previous(i).setNext(i, current.next(i));
             if (current.next(i) != null) {
diff --git a/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java b/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
index 16d1a015a4d9..53707ffab1b6 100644
--- a/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
+++ b/src/test/java/com/thealgorithms/datastructures/lists/SkipListTest.java
@@ -106,6 +106,20 @@ void testClearViaRemovals() {
         assertEquals(0, skipList.size());
     }
 
+    @Test
+    @DisplayName("Removing a missing element leaves the list unchanged")
+    void testRemoveMissing() {
+        skipList.remove("missing");
+        assertEquals(0, skipList.size());
+
+        skipList.add("a");
+        skipList.add("c");
+        skipList.remove("b");
+        assertEquals(2, skipList.size());
+        assertEquals("a", skipList.get(0));
+        assertEquals("c", skipList.get(1));
+    }
+
     private SkipList<String> createSkipList() {
         SkipList<String> s = new SkipList<>();
         String[] values = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k"};