Merge branch 'master' of https://github.com/manwar/perlweeklychallenge-club

1 files changed, 54 insertions, 0 deletions

diff --git a/challenge-169/michael-dicicco/java/ch1.java b/challenge-169/michael-dicicco/java/ch1.java
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+++ b/challenge-169/michael-dicicco/java/ch1.java
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+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ *
+ * @author mddicicco
+ */
+public class ch1 {
+
+    /**
+     * @param args the command line arguments
+     */
+    public static void main(String[] args) {
+        List<String> brilliants = new ArrayList<>();
+        for (long i = 4L; i < 300L; i++) {
+            if (isBrilliant(primeFactors(i))){
+                brilliants.add(Long.toString(i)); 
+            }
+        }
+        System.out.println(String.join(", ", brilliants));
+    }
+
+    public static Boolean isBrilliant(List<Long> factors) {
+        return (factors.size() == 2 && factors.get(0).toString().length() == factors.get(1).toString().length());
+    }
+
+    public static List<Long> primeFactors(long n) {
+        List<Long> output = new ArrayList<>();
+
+        // Print the number of 2s that divide n
+        while (n % 2L == 0L) {
+            output.add(2L);
+            n /= 2L;
+        }
+
+        // n must be odd at this point.  So we can
+        // skip one element (Note i = i +2)
+        for (long i = 3L; i <= Math.sqrt(n); i += 2L) {
+            // While i divides n, print i and divide n
+            while (n % i == 0) {
+                output.add(i);
+                n /= i;
+            }
+        }
+
+        // This condition is to handle the case when
+        // n is a prime number greater than 2
+        if (n > 2L) {
+            output.add(n);
+        }
+        return output;
+    }
+
+}