From 547f6addc7a9919c7b41d9cf42b54afe70674c57 Mon Sep 17 00:00:00 2001
From: lourenzo <81989+lourenzo@users.noreply.github.com>
Date: Mon, 13 Jul 2026 03:39:39 +0000
Subject: [PATCH] refactor: optimize isPrime by replacing stream with standard
 for loop

Replaced the LongStream implementation in isPrime with a standard primitive for-loop to eliminate stream allocation overhead. Fixed an underlying off-by-one bounds issue to correctly identify non-primes (like perfect squares 4 and 9) by using `<= limit`. Tested benchmark shows significant performance improvement.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
---
 src/PrimeToolKit.java | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/PrimeToolKit.java b/src/PrimeToolKit.java
index dc543dc..2a92dad 100644
--- a/src/PrimeToolKit.java
+++ b/src/PrimeToolKit.java
@@ -5,7 +5,12 @@ public class PrimeToolKit {
 
   // From exercise 003
   static boolean isPrime(long number) {
-    return number > 1 && range(2, Math.round(Math.sqrt(number))).noneMatch(i -> number % i == 0);
+    if (number <= 1) return false;
+    long limit = Math.round(Math.sqrt(number));
+    for (long i = 2; i <= limit; i++) {
+      if (number % i == 0) return false;
+    }
+    return true;
   }
 
   // From exercise 007