## Count 1 in binary array in java

Given a binary sorted non-increasing array arr of size N. You need to print the count of 1 in the binary array.

Try to solve the problem using binary search

#### Input

Each test case contains two lines. The first line contains N (size of binary array). The second line contains N elements of binary array separated by space.

### Output

In new line, print the count 1 in binary array.

#### Constraints:

1 <= N <= 10^6 arr[i] = 0,1

```8
1 1 1 1 1 0 0 0
```

```5
```

### Explaination

Number of 1 in given binary array : 1 1 1 1 1 0 0 0 is 5.

## Solution of Count 1 in binary array in java:–

```import java.util.*;
import java.lang.*;
import java.io.*;

public class Main
{
public static void main (String[] args) throws java.lang.Exception
{
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();

int arr[] = new int[n];

for(int i=0;i<n;i++)
{
arr[i]=sc.nextInt();
}

int l=0;
int r=n-1;

int ans=n;
while(l<=r)
{
int mid=(l+r)/2;
if(arr[mid]==0)
{
ans=mid;
r=mid-1;

}
else{
l=mid+1;
}
}
System.out.println(ans);
}
}```