53 lines
1.4 KiB
Text
53 lines
1.4 KiB
Text
inductive Tree
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| nil
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| node (l r : Tree)
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instance : Inhabited Tree := ⟨.nil⟩
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-- This function has an extra argument to suppress the
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-- common sub-expression elimination optimization
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partial def make' (n d : UInt32) : Tree :=
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if d = 0 then .node .nil .nil
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else .node (make' n (d - 1)) (make' (n + 1) (d - 1))
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-- build a tree
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def make (d : UInt32) := make' d d
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def check : Tree → UInt32
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| .nil => 0
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| .node l r => 1 + check l + check r
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def minN := 4
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def out (s : String) (n : Nat) (t : UInt32) : IO Unit :=
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IO.println s!"{s} of depth {n}\t check: {t}"
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-- allocate and check lots of trees
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partial def sumT (d i t : UInt32) : UInt32 :=
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if i = 0 then t
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else
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let a := check (make d)
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sumT d (i-1) (t + a)
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def main : List String → IO UInt32
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| [s] => do
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let n := s.toNat!
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let maxN := Nat.max (minN + 2) n
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let stretchN := maxN + 1
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-- stretch memory tree
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let c := check (make $ UInt32.ofNat stretchN)
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out "stretch tree" stretchN c
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-- allocate a long lived tree
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let long := make $ UInt32.ofNat maxN
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-- allocate, walk, and deallocate many bottom-up binary trees
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for d in [minN:maxN+1:2] do
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let n := 2 ^ (maxN - d + minN)
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let i := sumT (.ofNat d) (.ofNat n) 0
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out s!"{n}\t trees" d i
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-- confirm the long-lived binary tree still exists
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out "long lived tree" maxN (check long)
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return 0
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| _ => return 1
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