  We report a Dalitz-plot analysis of the charmless hadronic decays of charged
B mesons to the final state K+/- pi+/- pi-/+. Using a sample of 383.2 +/- 4.2
million BBbar pairs collected by the BaBar detector, we measure CP-averaged
branching fractions and direct CP asymmetries for intermediate resonant and
nonresonant contributions. We find evidence for direct CP violation in the
decay B+ -> rho0(770) K+, with a CP violation parameter A_CP = (+44 +/- 10 +/-
4 +5,-13)%.
