tree_depth(r1,r2;t) [data_tree(t, data)] { local i, j, di1, di2, dj1, dj2; if (t == NULL) { r1 = 0; r2 = 0; } else { i = t->l; j = t->r; tree_depth(di1, di2; i); tree_depth(dj1, dj2; j); if (di1 < dj1) r1 = dj1 + 1; else r1 = di1 + 1; if (di2 < dj2) r2 = di2 + 1; else r2 = dj2 + 1; } } [data_tree(t,data) * (r1 == ``MAX_DEPTH data``) * (r2 == ``MIN_DEPTH data``)]