problem no 19: Binary search.

 QUESTION:

Binary Search

Basic Accuracy: 38.43% Submissions: 69401 Points: 1

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Given a sorted array of size N and an integer K, find the position at which K is present in the array using binary search.

Example 1:

Input:
N = 5
arr[] = {1 2 3 4 5} 
K = 4
Output: 3
Explanation: 4 appears at index 3.

Example 2:

Input:
N = 5
arr[] = {11 22 33 44 55} 
K = 445
Output: -1
Explanation: 445 is not present.

ANSWER:

//the below function will be called when needed. 

int binsearch(int array[],int start_index,int end_index,int element)
{
    if(end_index>=start_index)
    {
        int middle=start_index+(end_index-start_index)/2;
        if(array[middle]==element)
        {
            return middle;
        }
        if(array[middle]>element)
        {
            return binsearch(array,start_index,middle-1,element);
        }
        else
        {
            return binsearch(array,middle+1,end_index,element);
        }
    }
    return -1;
}
 

 //below is the main function that we are gonna solve.

int binarysearch(int arr[], int n, int k){
       
       int i=0,j=n-1;
       
       int loc=binsearch(arr,i,j,k);
       return loc;
    }