diff --git a/lib/primes/Cargo.toml b/lib/primes/Cargo.toml
index 0bdd18b..7a66359 100644
--- a/lib/primes/Cargo.toml
+++ b/lib/primes/Cargo.toml
@@ -11,7 +11,6 @@ num = "*"
 [dev-dependencies]
 criterion = "*"
 
-
 [[bench]]
 name = "benchmark"
 harness = false
diff --git a/src/euler54/Cargo.toml b/src/euler54/Cargo.toml
index bda6e5d..45649ff 100644
--- a/src/euler54/Cargo.toml
+++ b/src/euler54/Cargo.toml
@@ -11,8 +11,6 @@ path = "src/lib.rs"
 name = "euler54"
 path = "src/main.rs"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
 [dependencies]
 rstest = "*"
 
@@ -21,6 +19,8 @@ criterion = "*"
 
 [profile.release]
 debug = true
+lto = true
+codegen-units = 1
 
 [[bench]]
 name = "benchmark"
diff --git a/src/euler54/src/card.rs b/src/euler54/src/card.rs
index 087be29..cd07939 100644
--- a/src/euler54/src/card.rs
+++ b/src/euler54/src/card.rs
@@ -51,10 +51,7 @@ impl Cards {
     }
 
     pub fn have_matching_suits(&self) -> bool {
-        self.array[1..]
-            .iter()
-            .zip(self.array[..4].iter())
-            .all(|(c1, c2)| c1.suit == c2.suit)
+        self.suit_hashset.len() == 1
     }
 
     pub fn contain_all_values_of(&self, values: &Values) -> bool {