Improve performance of Candidate in HashMap by simplifying equality check

src/constraints.rs

@@ -775,6 +775,7 @@ pub fn init_repeat_count<N: Number>(election: &mut Election<N>) {
 	let mut new_candidates = Vec::new();
 	for candidate in &election.candidates {
 		let mut new_candidate = candidate.clone();
+		new_candidate.index += election.candidates.len(); // Ensure unique index
 		new_candidate.is_dummy = true;
 		new_candidates.push(new_candidate);
 	}

src/election.rs

@@ -100,7 +100,7 @@ impl<N: Number> Election<N> {
 }
 
 /// A candidate in an [Election]
-#[derive(Clone, Eq, PartialEq)]
+#[derive(Clone, Eq)]
 #[cfg_attr(not(target_arch = "wasm32"), derive(Archive, Deserialize, Serialize))]
 pub struct Candidate {
 	/// Index of the candidate
@@ -111,13 +111,21 @@ pub struct Candidate {
 	pub is_dummy: bool,
 }
 
+impl PartialEq for Candidate {
+	// Custom implementation of eq for HashMap purposes, to improve performance
+	//
+	// SAFETY: Results in undefined behaviour if multiple Candidates are allowed to have the same index
+	fn eq(&self, other: &Candidate) -> bool {
+		return self.index == other.index;
+	}
+}
+
 impl Hash for Candidate {
 	fn hash<H: Hasher>(&self, hasher: &mut H) {
 		// Custom implementation of hash for use with NoHashHasher, to improve performance
 		hasher.write_usize(self.index);
 	}
 }
-
 impl nohash_hasher::IsEnabled for Candidate {}
 
 /// The current state of counting an [Election]