import numpy as np

def crossover(parents: np.ndarray, n_pop: int) -> np.ndarray:
    n_parents, n_decap = parents.shape

    # Split genomes into two halves
    left_halves = parents[:, :n_decap // 2]
    right_halves = parents[:, n_decap // 2:]

    # Create parent pairs
    parents_idx = np.stack([np.random.choice(range(n_parents), 2, replace=False) for _ in range(n_pop)])
    parents_left = left_halves[parents_idx[:, 0]]
    parents_right = right_halves[parents_idx[:, 1]]

    # Create offspring
    offspring = np.concatenate([parents_left, parents_right], axis=1)
    return offspring