Fix negative number hanging error

callumjamesfortune · Apr 26, 2024 · 9b4c0e9 · 9b4c0e9
1 parent 7bf9520
commit 9b4c0e9
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diff --git a/src/miller_rabin.rs b/src/miller_rabin.rs
@@ -4,6 +4,11 @@ use num_integer::Integer;
 use rand::thread_rng;
 
 pub fn miller_rabin(candidate: &BigInt) -> bool {
+
+    if candidate < &BigInt::from(0) {
+        return false;
+    }
+
     if candidate.is_even() {
         return *candidate == BigInt::from(2); // 2 is prime
     }

diff --git a/tests/miller_rabin_test.rs b/tests/miller_rabin_test.rs
@@ -5,6 +5,20 @@ mod tests {
     use super::*;
     use num_bigint::BigInt;
 
+    #[test]
+    fn test_negative_numbers() {
+
+        let primes = vec![
+            BigInt::from(-150),
+            BigInt::from(-3),
+            BigInt::from(0),
+            BigInt::from(-1005050)
+        ];
+        for prime in primes {
+            assert_eq!(miller_rabin(&prime), false);
+        }
+    }
+
     #[test]
     fn test_primes() {