Problem in logic building

#1

I am unable to understand exactly what question want to say

#2

@abhishekpandeycsaiml21_c74cb0ea3a791122
According to the Problem the work is to find the Max CB numbers from the given number.

  • As to work on substrings of the given number, we will capture the element into the String instead of integer .
  • The number ‘n’ given is nothing to do with our approach(as we are working on String) but can be useful acoording to your approach.

Intuition :

  • Put loop on string that will give substring of every length.
  • create a function that will return true if the passed number is a CB number otherwise return false.
  • To put a check if the digit is already a part of the any other CB number, create an boolean array say, valid which store which digits till now has been a part of any other CB number.
  • Take a counter and increment if a CB number is found.
  • At the end print the count.
public class cbNos {
    public static void main(String[] args) {
        Scanner scn = new Scanner(System.in);
        scn.nextInt();
        String str = scn.next();
        int count = 0;
        boolean[] visited = new boolean[str.length()];

        for (int len = 1; len <= str.length(); len++) {

            for (int si = 0; si <= str.length() - len; si++) {

                int ei = si + len;

                String ss = str.substring(si, ei);

                if (isCBNo(Long.valueOf(ss)) && isValid(visited, si, ei)) {

                    count++;

                    for (int i = si; i < ei; i++) {
                        visited[i] = true;
                    }

                }
            }

        }

        System.out.println(count);

    }

    public static boolean isValid(boolean[] visited, int start, int end) {

        for (int i = start; i < end; i++) {
            if (visited[i]) {
                return false;
            }
        }

        return true;
    }

    public static boolean isCBNo(long n) {

        if (n == 0 || n == 1) {
            return false;
        }

        long[] arr = { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 };

        for (int i = 0; i < arr.length; i++) {
            if (n == arr[i]) {
                return true;
            }
        }

        for (int i = 0; i < arr.length; i++) {
            if (n % arr[i] == 0) {
                return false;
            }
        }

        return true;
    }

  }
#3

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