Create RedJohnIsBack.java

Author: Foxeyyy

RedJohnIsBack.java

@@ -0,0 +1,75 @@
+import java.io.*;
+import java.math.*;
+import java.security.*;
+import java.text.*;
+import java.util.*;
+import java.util.concurrent.*;
+import java.util.regex.*;
+
+public class Solution {
+
+    // Complete the redJohn function below.
+    static int redJohn(int n) {
+
+        int m = numWays(n, new HashMap<>());
+        return primes(m);
+
+    }
+
+    static int numWays(int n, Map<Integer, Integer> memo) {
+        if (memo.containsKey(n)) return memo.get(n);
+        if (n == 4) return 2;
+        if (n < 4) return 1;
+
+        int result = numWays(n - 1, memo) + numWays(n - 4, memo);
+
+        memo.put(n, result);
+
+        return result;
+    }
+
+    static int primes(int m) {
+        int num = 0;
+
+        for(int i = 0; i <= m; i++) {
+            if (isPrime(i)) num++;
+        }
+
+        return num;
+    }
+
+    static boolean isPrime(int n) {
+
+        if (n < 2) return false;
+ 
+
+        for(int i = 2; i <= Math.sqrt(n); i++) {
+            if (n % i == 0) return false;
+        }
+
+        return true;
+    }
+
+    private static final Scanner scanner = new Scanner(System.in);
+
+    public static void main(String[] args) throws IOException {
+        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));
+
+        int t = scanner.nextInt();
+        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
+
+        for (int tItr = 0; tItr < t; tItr++) {
+            int n = scanner.nextInt();
+            scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
+
+            int result = redJohn(n);
+
+            bufferedWriter.write(String.valueOf(result));
+            bufferedWriter.newLine();
+        }
+
+        bufferedWriter.close();
+
+        scanner.close();
+    }
+}