Question

What indexes will be examined as the middle element by a binary search for the target value 8 when the search is run on the following input array? Check if the input array is in sorted order. What can you say about the binary search algorithm’s result?

int[] numbers = {6, 5, 8, 19, 7, 35, 22, 11, 9};

int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9};

(Using Java code please)

Answer 1

int[] numbers = {6, 5, 8, 19, 7, 35, 22, 11, 9}; for this array it will not work as it is not in the sorted order

int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9};

here first we will check with as 5 as it is middle element

next as 8>5 we will move right and check with 7

so next 8>7 we will move to right and check with 8

so 8==8 we will return true

public class BinarySearchIterative {
   public static void main(String[] args) {
       int[] numbers1 = {1, 2, 3, 4, 5, 6, 7, 8, 9};
       int[] numbers2= {6, 5, 8, 19, 7, 35, 22, 11, 9};
       System.out.println(binarySearch(numbers1, 8));
       System.out.println(binarySearch(numbers2, 8));
   }
   public static int binarySearch(int sortedArray[], int x)
{
       if(!isItSorted(sortedArray))
           return -1;
int l = 0, r = sortedArray.length - 1;
while (l <= r) {
int m = l + (r - l) / 2;
System.out.println(sortedArray[m]);
if (sortedArray[m] == x)
return m;
  
// If x greater, ignore left sub array
if (sortedArray[m] < x)
l = m + 1;
  
// If x is smaller, ignore right sub array
else
r = m - 1;
}
return -1;
}
   private static boolean isItSorted(int[] arr) {
       for(int i=0;i<arr.length-1;i++) {
           if(!(arr[i]<arr[i+1]))
               return false;
       }
       return true;
   }
}