[euler/prob009] add O(N) version

Author: gerdr

euler/prob009-gerdr.pl

@@ -0,0 +1,16 @@
+use v6;
+
+sub first-triple(\N) {
+	for 1..(N div 3) -> \a {
+		my \u = N * (N - 2 * a);
+		my \v = 2 * (N - a);
+
+		if u %% v {
+			my \b = u div v;
+			my \c = N - a - b;
+			return a, b, c;
+		}
+	}
+}
+
+say [*] first-triple(1000);