From 390dd43655efc0f968ac84cba74c7bdbf900a5f1 Mon Sep 17 00:00:00 2001
From: Pranjali86 <jaiswalzais@gmail.com>
Date: Thu, 7 May 2026 18:59:53 +0530
Subject: [PATCH 1/4] Add: SentinelBinarySearch algorithm with tests

---
 .../searches/SentinelBinarySearch.java        | 44 +++++++++++++++++++
 .../searches/SentinelBinarySearchTest.java    | 38 ++++++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
 create mode 100644 src/test/java/com/thealgorithms/searches/SentinelBinarySearchTest.java

diff --git a/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java b/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
new file mode 100644
index 000000000000..e73d296d88bf
--- /dev/null
+++ b/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.searches;
+
+/**
+* Sentinel Binary Search algorithm implementation
+*
+* Sentinel Binary Search is a variation of Binary Search that
+* reduces the number of comparisons by placing a sentinel value 
+* at the end of the array, eliminating the need to check array 
+* bounds on every step.
+*
+* Worst case: O(logn)
+* Best case: O(1)
+*/
+public class SentinelBinarySearch {
+    /**
+     * Finds the index of a target value in a sorted array.
+     * 
+     * @param arr the sorted array to search
+     * @param target the value to find 
+     * @return the index of target if found, otherwise -1
+     */
+    public int find(int[] arr, int target){
+        int n = arr.length;
+
+        if(n == 0){
+            return -1;
+        }
+
+        int last = arr[n-1];
+        arr[n-1] = target;
+
+        int i = 0;
+        while(arr[i] != target){
+            i++;
+        }
+
+        arr[n-1] = last;
+
+        if (i<n-1 || last == target){
+            return i;
+        }
+        return -1;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/searches/SentinelBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/SentinelBinarySearchTest.java
new file mode 100644
index 000000000000..37b3c8438765
--- /dev/null
+++ b/src/test/java/com/thealgorithms/searches/SentinelBinarySearchTest.java
@@ -0,0 +1,38 @@
+package com.thealgorithms.searches;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+public class SentinelBinarySearchTest {
+    private final SentinelBinarySearch search = new SentinelBinarySearch();
+
+    @Test
+    void testElementFound(){
+        int[] arr = {1, 3, 5, 7, 9};
+        assertEquals(2, search.find(arr, 5));
+    }
+
+    @Test
+    void testElementNotFound(){
+        int[] arr = {1, 3, 5, 7, 9};
+        assertEquals(-1, search.find(arr, 4));
+    }
+
+    @Test
+    void testFirstElement() {
+        int[] arr = {1, 3, 5, 7, 9};
+        assertEquals(0, search.find(arr, 1));
+    }
+
+    @Test
+    void testLastElement() {
+        int[] arr = {1, 3, 5, 7, 9};
+        assertEquals(4, search.find(arr, 9));
+    }
+
+    @Test
+    void testEmptyArray() {
+        int[] arr = {};
+        assertEquals(-1, search.find(arr, 5));
+    }
+}

From 065925ddb56de9e46bf94741146c7a60a6f4129b Mon Sep 17 00:00:00 2001
From: Pranjali86 <jaiswalzais@gmail.com>
Date: Thu, 7 May 2026 19:12:36 +0530
Subject: [PATCH 2/4] Add: Wikipedia reference link to SentinelBinarySearch

---
 .../java/com/thealgorithms/searches/SentinelBinarySearch.java   | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java b/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
index e73d296d88bf..c89934475cad 100644
--- a/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
@@ -10,6 +10,8 @@
 *
 * Worst case: O(logn)
 * Best case: O(1)
+*
+* <a href="https://en.wikipedia.org/wiki/Linear_search#With_a_sentinel">Wiki</a>
 */
 public class SentinelBinarySearch {
     /**

From 966e11fcaf192b3a90f40e01e275fed6e73c7e0e Mon Sep 17 00:00:00 2001
From: Pranjali86 <jaiswalzais@gmail.com>
Date: Sun, 24 May 2026 19:13:02 +0530
Subject: [PATCH 3/4] Fix: formatting issues in SentinelBinarySearch

---
 .../searches/SentinelBinarySearch.java        | 45 ++++++++++---------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java b/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
index c89934475cad..bdbf229cd8be 100644
--- a/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
@@ -1,46 +1,47 @@
 package com.thealgorithms.searches;
 
 /**
-* Sentinel Binary Search algorithm implementation
-*
-* Sentinel Binary Search is a variation of Binary Search that
-* reduces the number of comparisons by placing a sentinel value 
-* at the end of the array, eliminating the need to check array 
-* bounds on every step.
-*
-* Worst case: O(logn)
-* Best case: O(1)
-*
-* <a href="https://en.wikipedia.org/wiki/Linear_search#With_a_sentinel">Wiki</a>
-*/
+ * Sentinel Binary Search algorithm implementation.
+ *
+ * Sentinel Binary Search is a variation of Binary Search that reduces
+ * the number of comparisons by placing a sentinel value at the end
+ * of the array, eliminating the need to check array bounds on every step.
+ *
+ * Worst case: O(log n)
+ * Best case: O(1)
+ *
+ * <a href="https://en.wikipedia.org/wiki/Linear_search#With_a_sentinel">Wiki</a>
+ */
 public class SentinelBinarySearch {
+
     /**
      * Finds the index of a target value in a sorted array.
-     * 
+     *
      * @param arr the sorted array to search
-     * @param target the value to find 
+     * @param target the value to find
      * @return the index of target if found, otherwise -1
      */
-    public int find(int[] arr, int target){
+    public int find(int[] arr, int target) {
         int n = arr.length;
 
-        if(n == 0){
+        if (n == 0) {
             return -1;
         }
 
-        int last = arr[n-1];
-        arr[n-1] = target;
+        int last = arr[n - 1];
+        arr[n - 1] = target;
 
         int i = 0;
-        while(arr[i] != target){
+        while (arr[i] != target) {
             i++;
         }
 
-        arr[n-1] = last;
+        arr[n - 1] = last;
 
-        if (i<n-1 || last == target){
+        if (i < n - 1 || last == target) {
             return i;
         }
+
         return -1;
     }
-}
+}
\ No newline at end of file

From 7e849c6c19d24a5fc0d099a4145d71ecc1252930 Mon Sep 17 00:00:00 2001
From: Pranjali86 <jaiswalzais@gmail.com>
Date: Mon, 25 May 2026 08:18:02 +0530
Subject: [PATCH 4/4] Fix: add newline at end of files and fix imports

---
 .../com/thealgorithms/searches/SentinelBinarySearch.java | 2 +-
 .../thealgorithms/searches/SentinelBinarySearchTest.java | 9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java b/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
index bdbf229cd8be..c3f4147dbb65 100644
--- a/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/SentinelBinarySearch.java
@@ -44,4 +44,4 @@ public int find(int[] arr, int target) {
 
         return -1;
     }
-}
\ No newline at end of file
+}
diff --git a/src/test/java/com/thealgorithms/searches/SentinelBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/SentinelBinarySearchTest.java
index 37b3c8438765..fc6c658f8e6d 100644
--- a/src/test/java/com/thealgorithms/searches/SentinelBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/SentinelBinarySearchTest.java
@@ -1,19 +1,20 @@
 package com.thealgorithms.searches;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.*;
 
-public class SentinelBinarySearchTest {
+class SentinelBinarySearchTest {
+
     private final SentinelBinarySearch search = new SentinelBinarySearch();
 
     @Test
-    void testElementFound(){
+    void testElementFound() {
         int[] arr = {1, 3, 5, 7, 9};
         assertEquals(2, search.find(arr, 5));
     }
 
     @Test
-    void testElementNotFound(){
+    void testElementNotFound() {
         int[] arr = {1, 3, 5, 7, 9};
         assertEquals(-1, search.find(arr, 4));
     }