Merge pull request #15 from shlomif/master

Euler: remove trailing space, fix grammar+spelling and add #188 .

euler/README

@@ -2,8 +2,8 @@ Project Euler
 =============
 http://projecteuler.net/
 
-This is a directory to post answers to project euler questions.  
+This is a directory to post answers to project euler questions.
 
-Use the file format prob000-author.pl replaceing 000 with the problem number and author with your name.  For example if I am eric256 and I answer problem one I will save it as prob001-eric256.pl
+Use the file format prob000-author.pl, while replacing "000" with the problem number and "author" with your name.  For example if I am eric256 and I answer problem No. 1, I will save it as prob001-eric256.pl
 
 Thanks for playing!

euler/prob188-shlomif.pl

@@ -0,0 +1,30 @@
+use v6;
+
+# Solve Project Euler’s Problem No. 188:
+# http://projecteuler.net/problem=188
+# “The Hyperexponentiation of a number.”
+
+sub hyperexp_modulo(int $base, int $exp, int $mod) returns int
+{
+    if $exp == 1
+    {
+        return ($base % $mod);
+    }
+
+    my Int $mod1 = $base;
+    my Int $e = 1;
+
+    while $mod1 != 1
+    {
+        ($mod1 *= $base) %= $mod;
+        $e++;
+    }
+
+    my int $mod_recurse = hyperexp_modulo($base, $exp - 1, $e);
+
+    return $base.expmod($mod_recurse, $mod);
+}
+
+# print hyperexp_modulo(3, 3, 1000), "\n";
+
+printf "Result == %08d\n", hyperexp_modulo(1777, 1855, 100_000_000);