Merge remote-tracking branch 'upstream/master'

1 files changed, 54 insertions, 0 deletions

diff --git a/challenge-169/adam-russell/java/ch-2.java b/challenge-169/adam-russell/java/ch-2.java
new file mode 100644
index 0000000000..47c8d7813e
--- /dev/null
+++ b/challenge-169/adam-russell/java/ch-2.java
@@ -0,0 +1,54 @@
+import java.util.ArrayList;
+
+class Achilles{
+    private static final double EPSILON = 1e-15;
+    private static ArrayList primeFactors(long n){
+        ArrayList factors = new ArrayList();    
+        while (n % 2 == 0){
+            factors.add(new Long(2));
+            n = n / 2;
+        }
+        for(long i = 3; i <= Math.sqrt(n); i = i + 2){
+            while (n % i == 0){
+                factors.add(new Long(i));
+                n = n / i;
+            }
+        }
+        if(n > 2)
+            factors.add(new Long(n));
+        return factors;  
+    }
+    
+    private static boolean isAchilles(int n){
+        ArrayList factors = primeFactors(n);
+        for(int i = 0; i < factors.size(); i++){
+            if(n % Math.pow(((Long)factors.get(i)).longValue() + 0.0, 2) != 0)
+                return false;
+        }
+        for(int i = 2; i <= Math.sqrt(n); i++) {
+            double d = Math.log(n) / Math.log(i);
+            if(Math.abs(d - Math.round(d)) < EPSILON)
+                return false; 
+        }
+        return true;
+    }
+    
+    public static ArrayList nAchilles(int n){
+        ArrayList achilles = new ArrayList();
+        int i = 1;
+        do{
+            i++;
+            if(isAchilles(i))
+                achilles.add(new Integer(i));
+        }while(achilles.size() < n);
+        return achilles;
+    }
+
+    public static void main(String[] args){        
+        ArrayList achilles = Achilles.nAchilles(20);
+        for(int i = 0; i < achilles.size() - 1; i++){
+            System.out.print(achilles.get(i) + ", ");
+        }
+        System.out.println(achilles.get(achilles.size() - 1));
+    }
+}
\ No newline at end of file