Sentinel Linear Search in Java

// Java Program to Implement
// Linear Search
import java.io.*;

// Driver Class
public class GFG {
    public static int linearSearch(int[] arr, int target) {
        for (int i = 0; i < arr.length; i++) {
              // Found the target element and return its index
            if (arr[i] == target) {
                return i; 
            }
        }
      
          // Target not found in the array
        return -1; 
    }
  
      // Main Function
    public static void main(String[] args) {
        int[] arr = { 4, 2, 7, 1, 9, 5 };
        int target = 7;
        int index = linearSearch(arr, target);
      
        if (index != -1) {
            System.out.println("Element found at index: " + index);
        } else {
            System.out.println("Element not found");
        }
    }
}

// Java Program for Implementation
// of Sentinel Linear Search
import java.io.*;

// Driver Class
public class GFG {
    public static int sentinelLinearSearch(int[] arr, int target) {
        int n = arr.length;
      
          // Store the last element
        int last = arr[n - 1]; 
          
          // Append target to end of the array         
        arr[n - 1] = target; 
        
        int i = 0;
        while (arr[i] != target) {
            i++;
        }
      
        if (i < n - 1 || last == target)
            return i;
        
          // Target not found in the array
        return -1; 
    }
  
      // Main Function
    public static void main(String[] args) {
        int[] arr = { 4, 2, 7, 1, 9, 5 };
        int target = 7;
        int index = sentinelLinearSearch(arr, target);
        
          if (index != -1) {
            System.out.println("Element found at index: " + index);
        } else {
            System.out.println("Element not found");
        }
    }
}