def METHOD_NAME(exclusions, n_atoms):
    """Returns an array mapping atoms to their nonbonded exclusion neighbors and an array
    that stores number of nonbonded exclusions made by each atom."""
    numexclusions = np.bincount(
        exclusions.reshape((exclusions.shape[0] * 2)))
    nbemap = np.zeros((n_atoms, numexclusions.max()), int)
    nbemap.fill(-1)
    index = np.zeros(n_atoms, int)
    for nbexclusion in exclusions:
        a, b = nbexclusion
        nbemap[a, index[a]] = b
        nbemap[b, index[b]] = a
        index[nbexclusion] += 1
    return nbemap, numexclusions