DSA Day 20/100

Topic: Searching

Questions Successfully Completed: 1

Count 1's in a binary array

Time Complexity : O(log n)

Space Complexity : O(1)

    public static int countOnes(int arr[], int N){

        int low  = 0;
        int high = N-1;

        while(low<=high){
            int mid = (low + high)/2;
            if(arr[mid]==1){
                if((mid == N-1)||(arr[mid+1]==0) ){
                    return mid+1;
                }
                else {
                    low = mid + 1;
                }
            }
            else{
                high = mid -1;
            }
        }
        return 0;
    }

Thank you for reading :)