# Ronny’s confidence level (C) is 0. You have aseries of K exercises each of which increases Ronny’s confidence by P[K]

How to attempt?Question :Numbers Ronny’s confidence level (C) is 0. You have aseries of K exercises each of which increases
Ronny’s confidence by P[K] units (where P[K] is
a set of K prime numbers, [2, 3, 5, 7, …. ]),
respectively
Ronny practices exactly 1 exercise each
day. The same exercise can be practiced over
and over again. Find the minimum number of
days it will take for his confidence level to reac
exactly to D.
Input Specification:
input1: D, final confidence level.
input2: K, the total different number of
exercises.
Output Specification:
minimum number of days required to achieve the target. if not possible. output -1.​

Answer: xactly to D is 12
Input1: 12
Input2: 5
Output: 2
now since k is 5 therefore p[k]={2,3,5,7,11}exercise of p[k] value 5 and 7 will chosen to reach exactly 12

Source code for the following problem:-
import java.util.Scanner;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Main
{

public static void main(String[] args) {
Scanner sc= new Scanner(System.in);
int D ,K;
D= sc.nextInt();
K= sc.nextInt();
Integer[] dp = new Integer[1000];
Arrays.fill(dp,new Integer(-1));
List<Integer> DP = Arrays.asList(dp);
ArrayList<Integer> P = new ArrayList<>();
int i=2,k=0;
while(k < K){
if(isPrime(i)){
k++;
}
i++;
}
System.out.println(calculateConfidence(D,P,DP));
}
static final int INT_MAX = Integer.MAX_VALUE;
static int calculateConfidence(int D, ArrayList<Integer> P, List<Integer> dp)

{
if(D==0) return 0;
if(D<0) return INT_MAX;
if(dp.get(D) != -1)
return dp.get(D);
dp.set(D,INT_MAX);
for(int i=0;i<P.size()-1;i++)
{
int current = calculateConfidence(D-P.get(i),P,dp);
if(current == INT_MAX) continue;
dp.set(D,Math.min(dp.get(D),current+1));
}
return dp.get(D);
}

static boolean isPrime(int n){
if (n <= 1)
return false;
if (n <= 3)
return true;
if (n % 2 == 0 || n % 3 == 0)
return false;
for (int i = 5; i * i <= n; i = i + 6)
if (n % i == 0 || n % (i + 2) == 0)
return false;
return true;
}
}

The minimum number of days it will take for his confidence level to reach exactly to D is 12 .