Merge pull request #6196 from mikedici/challenge-167

challenge-167 entry

2 files changed, 89 insertions, 0 deletions

diff --git a/challenge-167/michael-dicicco/java/challenge167/circularprime.java b/challenge-167/michael-dicicco/java/challenge167/circularprime.java
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+++ b/challenge-167/michael-dicicco/java/challenge167/circularprime.java
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+package challenge167;
+
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+/**
+ *
+ * @author mddicicco
+ */
+public class circularprime {
+    public static Set<String> used_numbers = new LinkedHashSet<>();
+    public static boolean isPrime(int someNumber){
+        if (someNumber <= 1){
+            return false;
+        }
+        for(int i = 2; i < (someNumber - 1); i++){
+            if (someNumber % i == 0){
+                return false;
+            }
+        }
+        return true;
+    }
+    
+    public static String rotate(String someNumber){
+        // rotate to the left one character
+        return someNumber.substring(1,someNumber.length()) + someNumber.substring(0,1);
+    }
+    
+    public static boolean validate(String someNumber){
+        // check if the original string is prime
+        if (!isPrime(Integer.parseInt(someNumber))){
+            return false;
+        }
+        
+        String temp = someNumber;
+        // check if any rotations of the string are not prime
+        for(int i = 0; i < someNumber.length() - 1; i++){
+            temp = rotate(temp);
+            if (!isPrime(Integer.parseInt(temp))){
+                return false;
+            }
+            used_numbers.add(temp);
+        }
+        return true;
+    }
+}
diff --git a/challenge-167/michael-dicicco/java/challenge167/task1.java b/challenge-167/michael-dicicco/java/challenge167/task1.java
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+/*
+ * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
+ * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Main.java to edit this template
+ */
+package challenge167;
+
+/**
+ *
+ * @author mddicicco
+ */
+public class task1 {
+
+    /**
+     * Challenge 167 Task1
+     *
+     * Solution By: Michael DiCicco
+     *
+     * Write a script to find out first 10 circular primes having at least 3
+     * digits (base 10). Please checkout wikipedia for more information. A
+     * circular prime is a prime number with the property that the number
+     * generated at each intermediate step when cyclically permuting its (base
+     * 10) digits will also be prime.
+     *
+     * Output 113, 197, 199, 337, 1193, 3779, 11939, 19937, 193939, 199933
+     */
+    
+    public static void main(String[] args) {
+        String[] ten_circular_primes = new String[10];
+        String someNumber = "111";
+        int index = 0;
+        while (ten_circular_primes[9] == null) {
+            if (circularprime.validate(someNumber)) {
+                if (!circularprime.used_numbers.contains(someNumber)) {
+                    ten_circular_primes[index] = someNumber;
+                    index++;
+                }
+            }
+            someNumber = Integer.toString(Integer.parseInt(someNumber) + 1);
+        }
+        System.out.println(String.join(", ", ten_circular_primes));
+
+    }
+}