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

1 files changed, 70 insertions, 0 deletions

diff --git a/challenge-169/michael-dicicco/java/ch2.java b/challenge-169/michael-dicicco/java/ch2.java
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+++ b/challenge-169/michael-dicicco/java/ch2.java
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+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ *
+ * @author mddicicco
+ */
+public class ch2 {
+    static final double PRECISION = Math.pow(10,12);
+    public static void main(String[] args){
+        
+        List<String> achilles_nums = new ArrayList<>();
+        
+        for(long i = 72; i < 1801; i++){
+            if(isAchilles(primeFactors(i), i)){
+                achilles_nums.add(Long.toString(i));
+            }
+        }
+        System.out.println(String.join(", ", achilles_nums));
+    }
+    public static Boolean isAchilles(List<Long> factors, Long given){
+        for(Long factor : factors){
+            if(!(given % Math.pow(factor, 2) == 0))
+                return false;
+        }
+        
+        
+       
+        for(long i = 2; i <= 9; i++){
+            double root = Math.round(nthRoot(given, i) * PRECISION)/PRECISION;
+            
+            if (Math.floor(root) == root){
+                
+                return false;
+            }
+        }
+        return true;
+                
+    }
+    public static double nthRoot(double someNumber, double n){
+        return Math.pow(n, ((1.0 / n ) * (Math.log(someNumber) / Math.log(n))));
+    }
+    
+    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;
+    }
+}