- Added guest solutions by Laurent Rosenfeld.

1 files changed, 37 insertions, 0 deletions

diff --git a/challenge-175/laurent-rosenfeld/java/PerfectTotient.java b/challenge-175/laurent-rosenfeld/java/PerfectTotient.java
new file mode 100644
index 0000000000..7f46773ec8
--- /dev/null
+++ b/challenge-175/laurent-rosenfeld/java/PerfectTotient.java
@@ -0,0 +1,37 @@
+public class PerfectTotient {
+
+    static int[] cache = new int[10000];
+
+    public static int gcd(int i, int j) {
+        while (j != 0) {
+            int temp = i % j;
+            i = j;
+            j = temp;
+        }
+        return i;
+    }
+    public static boolean isPerfectTotient(int n) {
+        int tot = 0;
+        for (int i = 1; i < n; i++) {
+            if (gcd(n, i) == 1) {
+                tot++;
+            }
+        }
+        int sum = tot + cache[tot];
+        cache[n] = sum;
+        return n == sum;
+    }
+
+    public static void main(String[] args) {
+        int i = 0;
+        int count = 0;
+        while (count < 20) {
+            if (isPerfectTotient(i)) {
+                System.out.printf("%d ", i);
+                count++;
+            }
+            i++;
+        }
+        System.out.printf("%s", "\n");
+    }
+}