  We make a systematical diffusion Monte Carlo (DMC) calculation for all ground
state baryons in two confinement scenarios, the pairwise confinement and the
three-body flux-tube confinement. With the baryons as an example, we illustrate
a feasible procedure to investigate the few-quark states with possible few-body
confinement mechanisms, which can be extended to the multiquark states easily.
For each baryon, we extract the mass, mean-square radius, charge radius, and
the quark distributions. We use the Jackknife resampling method to estimate the
statistical uncertainties of masses to be less than 1 MeV. To determine the
baryon charge radii, we include the constituent quark size effect, which is
fixed by the experimental and lattice QCD results. Our results show that both
two-body and three-body confinement mechanisms can give a good description of
the experimental data if the parameters are chosen properly. In the flux-tube
confinement, introducing different tension parameters for the baryons and
mesons are necessary, specifically, $\sigma_Y= 0.9204 \sigma_{Q\bar{Q}}$. The
lesson from the calculation of the nucleon mass with the DMC method is that the
improper pre-assignment of the channels may prevent us from obtaining the real
ground state. With this experience, we obtain the real ground state (the
$\eta_c \eta_c$ threshold with the di-meson configuration) of the
$cc\bar{c}\bar{c}$ system with $J^{PC}=0^{++}$ starting from the
diquark-antidiquark spin-color channels alone, which is hard to achieve in the
variational method and was not obtained in the previous DMC calculations.
