Lechner, Hauke, and Zoller proposed a parity-encoded spin-embedding
scheme for quantum annealing (QA) with all-to-all connectivity to avoid
the issue of limited connectivity in near-term QA hardware and to enable
the implementation thereof using only geometrically local interactions
between spins fabricated on the planar substrate. Nevertheless, the
redundant encoding of logical information, i.e., using a large number of
spins to embed the logical information, increases the computational cost
and reduces the efficiency. In this study, we show through Monte Carlo
simulation that this redundant encoding may be exploited to solve the
problems of the inefficiency and computational cost of the
parity-encoded scheme by incorporating appropriate decoding, namely
classical post-processing, of the spins to retrieve the logical
information. Our findings open up the possibility of parity-encoded
schemes for realizing the QA with near-term quantum technologies.