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  1. Prepare
  2. Algorithms
  3. Dynamic Programming
  4. Red John is Back
  5. Discussions

Red John is Back

  • mandarbhatye
     + 0 comments

    public static int redJohn(int n) { int countWays = numberOfWays(n); int totalPrimes = sieve(countWays);

        return totalPrimes;
}

public static int numberOfWays(int N){
    if (N<=3) return 1;
    if (N==4) return 2;
    return numberOfWays(N-1) + numberOfWays(N-4);
}

public static int sieve(int n) {
    int count = 0;
    boolean prime[] = new boolean[n + 1];
    for (int i = 0; i <= n; i++)
        prime[i] = true;

    for (int p = 2; p * p <= n; p++)
        if (prime[p] == true)
            for (int i = p * 2; i <= n; i += p)
                prime[i] = false;

    for (int i = 2; i <= n; i++)
        if (prime[i] == true)
            count++;

    return count;
}