implement tournament_selection

src/main.odin

@@ -70,6 +70,21 @@ destroy_population :: proc(pop: ^Population) {
 	}
 }
 
+tournament_selection :: proc(pop: ^Population, fitnesses: []int, k: int = 3) -> ^Chromosome {
+	best_idx := rand.int_max(POPULATION_SIZE)
+	best_fitness := fitnesses[best_idx]
+
+	for _ in 1 ..< k {
+		idx := rand.int_max(POPULATION_SIZE)
+		if fitnesses[idx] < best_fitness {
+			best_idx = idx
+			best_fitness = fitnesses[idx]
+		}
+	}
+
+	return &pop[best_idx]
+}
+
 main :: proc() {
 	items, ok := read_data(DATA_FILE)
 	if !ok {