  The theoretical information threshold for the planted clique problem is
$2\log_2(N)$, however no polynomial algorithm is known to recover a planted
clique of size $O(N^{1/2-\epsilon})$, $\epsilon>0$. In this paper we will apply
a standard method for the analysis of disordered models, the Parallel-Tempering
(PT) algorithm, to the clique problem, showing numerically that its
time-scaling in the hard region is indeed polynomial for the analyzed sizes. We
also apply PT to a different but connected model, the Sparse Planted
Independent Set problem. In this situation thresholds should be sharper and
finite size corrections should be less important. Also in this case PT shows a
polynomial scaling in the hard region for the recovery.
