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chore: remove [Inhabited A] from binSearch / binInsert

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Mario Carneiro 2022-10-27 07:47:11 -04:00 • committed by Leonardo de Moura
parent c72cf24694
commit b948a56196
1 changed files with 9 additions and 6 deletions
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15
src/Init/Data/Array/BinSearch.lean
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@ -13,9 +13,10 @@ namespace Array
-- TODO: remove the [Inhabited α] parameters as soon as we have the tactic framework for automating proof generation and using Array.fget
-- TODO: remove `partial` using well-founded recursion
@[specialize] partial def binSearchAux {α : Type u} {β : Type v} [Inhabited α] [Inhabited β] (lt : α → α → Bool) (found : Option α → β) (as : Array α) (k : α) : Nat → Nat → β
@[specialize] partial def binSearchAux {α : Type u} {β : Type v} [Inhabited β] (lt : α → α → Bool) (found : Option α → β) (as : Array α) (k : α) : Nat → Nat → β
| lo, hi =>
if lo <= hi then
let _ := Inhabited.mk k
let m := (lo + hi)/2
let a := as.get! m
if lt a k then binSearchAux lt found as k (m+1) hi
@ -25,27 +26,28 @@ namespace Array
else found (some a)
else found none
@[inline] def binSearch {α : Type} [Inhabited α] (as : Array α) (k : α) (lt : α → α → Bool) (lo := 0) (hi := as.size - 1) : Option α :=
@[inline] def binSearch {α : Type} (as : Array α) (k : α) (lt : α → α → Bool) (lo := 0) (hi := as.size - 1) : Option α :=
if lo < as.size then
let hi := if hi < as.size then hi else as.size - 1
binSearchAux lt id as k lo hi
else
none
@[inline] def binSearchContains {α : Type} [Inhabited α] (as : Array α) (k : α) (lt : α → α → Bool) (lo := 0) (hi := as.size - 1) : Bool :=
@[inline] def binSearchContains {α : Type} (as : Array α) (k : α) (lt : α → α → Bool) (lo := 0) (hi := as.size - 1) : Bool :=
if lo < as.size then
let hi := if hi < as.size then hi else as.size - 1
binSearchAux lt Option.isSome as k lo hi
else
false
@[specialize] private partial def binInsertAux {α : Type u} {m : Type u → Type v} [Monad m] [Inhabited α]
@[specialize] private partial def binInsertAux {α : Type u} {m : Type u → Type v} [Monad m]
(lt : α → α → Bool)
(merge : α → m α)
(add : Unit → m α)
(as : Array α)
(k : α) : Nat → Nat → m (Array α)
| lo, hi =>
let _ := Inhabited.mk k
-- as[lo] < k < as[hi]
let mid := (lo + hi)/2
let midVal := as.get! mid
@ -57,12 +59,13 @@ namespace Array
else do
as.modifyM mid <| fun v => merge v
@[specialize] def binInsertM {α : Type u} {m : Type u → Type v} [Monad m] [Inhabited α]
@[specialize] def binInsertM {α : Type u} {m : Type u → Type v} [Monad m]
(lt : α → α → Bool)
(merge : α → m α)
(add : Unit → m α)
(as : Array α)
(k : α) : m (Array α) :=
let _ := Inhabited.mk k
if as.isEmpty then do let v ← add (); pure <| as.push v
else if lt k (as.get! 0) then do let v ← add (); pure <| as.insertAt! 0 v
else if !lt (as.get! 0) k then as.modifyM 0 <| merge
@ -70,7 +73,7 @@ namespace Array
else if !lt k as.back then as.modifyM (as.size - 1) <| merge
else binInsertAux lt merge add as k 0 (as.size - 1)
@[inline] def binInsert {α : Type u} [Inhabited α] (lt : α → α → Bool) (as : Array α) (k : α) : Array α :=
@[inline] def binInsert {α : Type u} (lt : α → α → Bool) (as : Array α) (k : α) : Array α :=
Id.run <| binInsertM lt (fun _ => k) (fun _ => k) as k
end Array