Floor_BS.java

public class Floor_BS {
    public static void main(String[] args) {
        int[] arr={1,2,3,4,5};
        int target = 4;
        int ans = floor(arr, target);
        System.out.println(ans);
}
    static int floor(int[] arr, int target){
        int start=0;
        int end = arr.length - 1;
        while(start <= end){
            int mid= start + (end-start) / 2;
            if(target < arr[mid]){
                end = mid-1;
            }
            else if(target > arr[mid]){
                start = mid+1;
            }
            else{
                return mid;
            }
        }
        return end;
    }
}
//FLOOR: greatest number <= target