From b0db23c78cb1b0291b645b87dae9d47faf9082ca Mon Sep 17 00:00:00 2001
From: Rutherther <rutherther@ditigal.xyz>
Date: Mon, 27 Oct 2025 20:45:35 +0100
Subject: [PATCH] feat: add best selection

---
 codes/eoa_lib/src/selection.rs | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/codes/eoa_lib/src/selection.rs b/codes/eoa_lib/src/selection.rs
index 48718b9d62374591cf51cae11eaa9aabadedf0dc..5485387628b8597cfc9a304eefd2bc61eb89ee2d 100644
--- a/codes/eoa_lib/src/selection.rs
+++ b/codes/eoa_lib/src/selection.rs
@@ -11,6 +11,30 @@ pub trait Selection<TChromosome, TResult> {
     ) -> impl Iterator<Item = usize>;
 }
 
+pub struct BestSelection;
+impl BestSelection {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl<TChromosome, TResult: Copy> Selection<TChromosome, TResult> for BestSelection {
+    fn select(&mut self,
+              count: usize,
+              evaluations: &EvaluatedPopulation<TChromosome, TResult>,
+              better_than: &dyn BetterThanOperator<TResult>
+    ) -> impl Iterator<Item = usize> {
+        let mut idxs = (0..evaluations.population.len())
+            .collect::<Vec<_>>();
+        idxs.sort_unstable_by(|&i, &j| better_than.ordering(
+            &evaluations.population[i].evaluation,
+            &evaluations.population[j].evaluation)
+        );
+
+        idxs.into_iter().take(count)
+    }
+}
+
 pub struct TournamentSelection {
     rng: Box<dyn RngCore>,
     p: f64,