text‹\noindent In Exercise~\ref{ex:Tree} we defined a function term‹flatten› from trees to lists. The straightforward version of term‹flatten› is based on ‹@› and is thus, like term‹rev›,
. A linear time version of term‹flatten› again reqires an extra
, the accumulator. Define› (*<*)primrec(*>*)flatten2 :: "'a tree \<Rightarrow> 'a list \<Rightarrow> 'a list"(*<*)where "flatten2 Tip xs = xs" | "flatten2 (Node l x r) xs = flatten2 l (x#(flatten2 r xs))" (*>*)
text‹\noindent and prove› (*<*) lemma [simp]: "∀xs. flatten2 t xs = flatten t @ xs" apply(induct_tac t) by(auto) (*>*) lemma"flatten2 t [] = flatten t" (*<*) by(simp)
end (*>*)
Messung V0.5 in Prozent
[zur Elbe Produktseite wechseln0.21QuellennavigatorsAnalyse erneut starten2026-09-28]
