74 lines
2.8 KiB
Text
74 lines
2.8 KiB
Text
/-
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Copyright (c) 2017 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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prelude
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import init.data.ordering.basic init.coe init.data.option.basic init.io
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universes u v w w'
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inductive color
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| Red | Black
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inductive Tree
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| Leaf {} : Tree
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| Node (color : color) (lchild : Tree) (key : Nat) (val : Bool) (rchild : Tree) : Tree
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variables {σ : Type w}
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open color Nat Tree
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def fold (f : Nat → Bool → σ → σ) : Tree → σ → σ
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| Leaf b := b
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| (Node _ l k v r) b := fold r (f k v (fold l b))
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def balance1 : Tree → Tree → Tree
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| (Node _ _ kv vv t) (Node _ (Node Red l kx vx r₁) ky vy r₂) := Node Red (Node Black l kx vx r₁) ky vy (Node Black r₂ kv vv t)
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| (Node _ _ kv vv t) (Node _ l₁ ky vy (Node Red l₂ kx vx r)) := Node Red (Node Black l₁ ky vy l₂) kx vx (Node Black r kv vv t)
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| (Node _ _ kv vv t) (Node _ l ky vy r) := Node Black (Node Red l ky vy r) kv vv t
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| _ _ := Leaf
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def balance2 : Tree → Tree → Tree
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| (Node _ t kv vv _) (Node _ (Node Red l kx₁ vx₁ r₁) ky vy r₂) := Node Red (Node Black t kv vv l) kx₁ vx₁ (Node Black r₁ ky vy r₂)
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| (Node _ t kv vv _) (Node _ l₁ ky vy (Node Red l₂ kx₂ vx₂ r₂)) := Node Red (Node Black t kv vv l₁) ky vy (Node Black l₂ kx₂ vx₂ r₂)
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| (Node _ t kv vv _) (Node _ l ky vy r) := Node Black t kv vv (Node Red l ky vy r)
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| _ _ := Leaf
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def isRed : Tree → Bool
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| (Node Red _ _ _ _) := true
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| _ := false
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def ins : Tree → Nat → Bool → Tree
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| Leaf kx vx := Node Red Leaf kx vx Leaf
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| (Node Red a ky vy b) kx vx :=
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(if kx < ky then Node Red (ins a kx vx) ky vy b
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else if kx = ky then Node Red a kx vx b
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else Node Red a ky vy (ins b kx vx))
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| (Node Black a ky vy b) kx vx :=
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if kx < ky then
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(if isRed a then balance1 (Node Black Leaf ky vy b) (ins a kx vx)
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else Node Black (ins a kx vx) ky vy b)
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else if kx = ky then Node Black a kx vx b
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else if isRed b then balance2 (Node Black a ky vy Leaf) (ins b kx vx)
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else Node Black a ky vy (ins b kx vx)
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def setBlack : Tree → Tree
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| (Node _ l k v r) := Node Black l k v r
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| e := e
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def insert (t : Tree) (k : Nat) (v : Bool) : Tree :=
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if isRed t then setBlack (ins t k v)
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else ins t k v
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def mkMapAux : Nat → Tree → Tree
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| 0 m := m
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| (n+1) m := mkMapAux n (insert m n (n % 10 = 0))
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def mkMap (n : Nat) :=
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mkMapAux n Leaf
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def main (xs : List String) : IO UInt32 :=
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let m := mkMap xs.head.toNat in
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let v := fold (λ (k : Nat) (v : Bool) (r : Nat), if v then r + 1 else r) m 0 in
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IO.println (toString v) *>
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pure 0
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