Pure-R implementation of univariate binary-class ODA (UniODA), univariate multiclass ODA (MultiODA), and binary Classification Tree Analysis (CTA). Supports ordered and categorical attributes, priors-on inverse-frequency weighting, MAXSENS / SAMPLEREP / first-identified tie-breaking, true leave-one-out cross-validation, and Monte Carlo Fisher-randomization p-values. Covered UniODA, MultiODA, and binary CTA fixtures are tested for parity against MegaODA.exe and CTA.exe outputs.