import init.data.persistentarray

abbrev MyArray := PersistentArray Nat
-- abbrev MyArray := Array Nat

def mkMyArray (n : Nat) : MyArray :=
n.fold (λ i s => s.push i) { PersistentArray . }
-- n.fold (λ i s, s.push i) Array.empty

def check (n : Nat) (p : Nat → Nat → Bool) (s : MyArray) : IO Unit :=
n.mfor $ λ i => unless (p i (s.get i)) (throw (IO.userError ("failed at " ++ toString i ++ " " ++ toString (s.get i))))

def inc1 (n : Nat) (s : MyArray) : MyArray :=
n.fold (λ i s => s.set i (s.get i + 1)) s

def checkId (n : Nat) (s : MyArray) : IO Unit :=
check n (fun a b => a == b) s

def main (xs : List String) : IO Unit :=
do
let n := xs.head.toNat;
let t := mkMyArray n;
checkId n t;
let t := inc1 n t;
check n (λ i v => v == i + 1) t;
IO.println t.size;
IO.println t.stats;
pure ()