Add SentinelLinearSearch.java and Update README.md

README.md

@@ -420,13 +420,13 @@ In order to achieve greater coverage and encourage more people to contribute to
                 </a>
             </td>
             <td> <!-- C++ -->
-                <a href="./CONTRIBUTING.md">
+                <a href="./src/java/CONTRIBUTING.md">
                     <img align="center" height="25" src="./logos/github.svg" />
                 </a>
             </td>
             <td> <!-- Java -->
-                <a href="./CONTRIBUTING.md">
-                    <img align="center" height="25" src="./logos/github.svg" />
+                <a href="./src/java/SentinelLinearSearch.java.md">
+                    <img align="center" height="25" src="./logos/java.svg" />
                 </a>
             </td>
             <td> <!-- Python -->

src/java/SentinelLinearSearch.java

@@ -0,0 +1,32 @@
+public class SentinelLinearSearch {
+    public static void main(String[] args){
+        int[] arr = {10,20,50,60,30,60,70,80,22,56,2,7,9,0,44};
+        System.out.println(LinearSentinel(arr,70));
+        System.out.println(LinearSentinel(arr,45));
+    }   
+
+    public static int LinearSentinel(int[] arr, int key){
+
+        int n = arr.length;
+
+        // Storing last element.
+        int last = arr[n-1];
+
+        // Adding key at end index + 1
+        arr[n-1] = key;
+
+        int i = 0;
+        for(i = 0; i<n;i++){
+            if(arr[i] == key) break;
+        }
+
+        // Restoring the last element
+        arr[n-1] = last;
+
+        // Returning index when found.
+        if((i<n-1) || arr[n-1] == key){ return i;}
+
+        // Returning -1 if not found
+        else return -1;
+    }
+}