274 lines
9.3 KiB
Standard ML
274 lines
9.3 KiB
Standard ML
structure SearchList =
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struct
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type t = {left: int vector list, right: int vector list}
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val targetLength = 1024
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val empty: t = {left = [], right = []}
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fun isLessThanTarget (v1, v2) =
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Vector.length v1 + Vector.length v2 <= targetLength
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fun isThreeLessThanTarget (v1, v2, v3) =
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Vector.length v1 + Vector.length v2 + Vector.length v3 <= targetLength
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fun joinEndOfLeft (new, left) =
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case left of
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hd :: tail =>
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if isLessThanTarget (new, hd) then
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let val newHd = Vector.concat [hd, new]
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in newHd :: tail
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end
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else
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new :: left
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| [] => new :: left
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fun joinStartOfRight (new, right) =
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case right of
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hd :: tail =>
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if isLessThanTarget (new, hd) then
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let val newHd = Vector.concat [new, hd]
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in newHd :: tail
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end
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else
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new :: right
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| [] => new :: right
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fun insMiddle (new, hd, tl, left, right) =
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let
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val middle = BinSearch.equalOrMore (new, hd)
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val leftSlice = VectorSlice.slice (hd, 0, SOME middle)
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val rightLength = Vector.length hd - middle
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val rightSlice = VectorSlice.slice (hd, middle, SOME rightLength)
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val new = Vector.fromList [new]
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val new = VectorSlice.full new
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in
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if Vector.length hd < targetLength then
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let val newHd = VectorSlice.concat [leftSlice, new, rightSlice]
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in {left = joinEndOfLeft (newHd, tl), right = right}
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end
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else if middle < targetLength then
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(* leftSlice is less than targetLength *)
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let
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val hd1 = VectorSlice.concat [leftSlice, new]
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val hd2 = VectorSlice.vector rightSlice
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in
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{ left = joinEndOfLeft (hd1, tl)
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, right = joinStartOfRight (hd2, right)
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}
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end
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else
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let
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val hd1 = VectorSlice.vector leftSlice
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val hd2 = VectorSlice.concat [new, rightSlice]
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in
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{ left = joinEndOfLeft (hd1, tl)
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, right = joinStartOfRight (hd2, right)
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}
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end
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end
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fun insLeft (new, left, right) =
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case left of
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hd :: tl =>
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let
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val first = Vector.sub (hd, 0)
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in
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if new < first then
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insLeft (new, tl, joinStartOfRight (hd, right))
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else if new > first then
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let
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val last = Vector.sub (hd, Vector.length hd - 1)
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in
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if new < last then
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(* have to insert in middle *)
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insMiddle (new, hd, tl, left, right)
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else if new > last then
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(* have to insert new at end of left
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* or start of right (both are equivalent) *)
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{ left = left
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, right = joinStartOfRight (Vector.fromList [new], right)
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}
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else
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(* new = last so just return *)
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{left = left, right = right}
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end
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else
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(* new = first *)
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{left = left, right = right}
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end
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| [] => {left = left, right = right}
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fun insRight (new, left, right) =
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case right of
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hd :: tl =>
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let
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val last = Vector.sub (hd, Vector.length hd - 1)
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in
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if new > last then
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insRight (new, joinEndOfLeft (hd, left), tl)
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else if new < last then
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let
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val first = Vector.sub (hd, 0)
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in
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if new > first then
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(* have to insert in middle *)
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insMiddle (new, hd, tl, left, right)
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else if new < first then
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(* have to insert new at start of right
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* or end of left (both are equivalent) *)
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{ left = left
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, right = joinStartOfRight (Vector.fromList [new], right)
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}
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else
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(* new = first so just return *)
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{left = left, right = right}
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end
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else
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(* new = last *)
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{left = left, right = right}
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end
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| [] => {left = left, right = right}
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fun insert (new, {left, right}: t) =
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(* look at elements to see which way to traverse *)
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case right of
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hd :: _ =>
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if Vector.sub (hd, 0) >= new then insRight (new, left, right)
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else insLeft (new, left, right)
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| [] => insLeft (new, left, right)
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fun helpGoToNumLeft (num, left, right) =
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case left of
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hd :: tl =>
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if num < Vector.sub (hd, 0) then
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(* continue *)
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helpGoToNumLeft (num, tl, joinStartOfRight (hd, right))
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else
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(* greater or equal to first element so return.
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* Note: caller which destructures list expects found hd to always be
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* on right. *)
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{left = tl, right = joinStartOfRight (hd, right)}
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| [] => {left = left, right = right}
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fun helpGoToNumRight (num, left, right) =
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case right of
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hd :: tl =>
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if num > Vector.sub (hd, Vector.length hd - 1) then
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(* continue *)
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helpGoToNumRight (num, joinEndOfLeft (hd, left), tl)
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else
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(* less than or equal to last element so return *)
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{left = left, right = right}
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| [] => {left = left, right = right}
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fun goToNum (num, {left, right}: t) =
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case right of
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hd :: tl =>
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if num > Vector.sub (hd, Vector.length hd - 1) then
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helpGoToNumRight (num, left, right)
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else
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helpGoToNumLeft (num, left, right)
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| [] => helpGoToNumLeft (num, left, right)
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fun delRightFromHere (finish, left, right) =
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case right of
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hd :: tl =>
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let
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val last = Vector.sub (hd, Vector.length hd - 1)
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in
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if last < finish then
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delRightFromHere (finish, left, tl)
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else if last > finish then
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let
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val delpoint = BinSearch.equalOrMore (last, hd)
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val newHd = VectorSlice.slice (hd, 0, SOME delpoint)
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val newHd = VectorSlice.vector newHd
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in
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{ left = left, right = joinStartOfRight (newHd, right) }
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end
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else if last = finish then
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{ left = left, right = tl }
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| [] => { left = left, right = right }
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fun del (start, finish, left, right) =
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case right of
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rhd :: rtl =>
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let
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val rfirst = Vector.sub (rhd, 0)
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in
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if start < rfirst then
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(case left of
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lhd :: ltl =>
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let
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val llast = Vector.sub (lhd, Vector.length lhd - 1)
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in
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if
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start < llast
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then
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if finish < rfirst then
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(* start < rfirst and start < llast and finish < rfirst
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* move left and delete *)
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moveLeftAndDelete (start, finish, left, right)
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else
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(* start < rfirst and start < llast and finish >= rfirst
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* in middle; delete from both sides *)
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delFromLeftAndRight (start, finish, left, right)
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else if
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start = llast
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then
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if finish < rfirst then
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(* start < rfirst, start = llast, and finish < rfirst
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* so just have to delete left from here *)
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deleteLeftFromHere (start, left, right)
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else
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(* start < rfirst, start = llast, finish >= rfirst
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* in middle; delete from both sides *)
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delFromLeftAndRight (start, finish, left, right)
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else (* start > llast and start < rfirst *) if
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finish >= rfirst
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then
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(* delete right from here *)
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delRightFromHere (finish, left, right)
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else
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(* start < rfirst and finish < rfirst
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* so just return *)
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{left = left, right = right}
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end
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| [] =>
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(* start < rfirst
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* but left is empty.
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* All we can do is 1. Delete right or 2. Return *)
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if finish < rfirst then {left = left, right = right}
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else delRightFromHere (finish, left, right))
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else if start = rfirst then
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delRightFromHere (finish, left, right)
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else
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(* start > rfirst
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* move right and then start deleting *)
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moveRightAndDelete (start, finish, left, right)
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end
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| [] =>
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(case left of
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lhd :: ltl =>
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let
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val llast = Vector.sub (lhd, Vector.length lhd - 1)
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in
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if start < llast then
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if finish <= llast then
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moveRightAndDelete (start, finish, left, right)
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else
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deleteLeftFromHere (finish, left, right)
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else
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moveRightAndDelete (start, finish, left, right)
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end
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| [] =>
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(* left and right are both empty *)
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{left = left, right = right})
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fun delete (start, length, {left, right}: t) =
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if length > 0 then del (start, start + length, left, right)
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else {left = left, right = right}
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end
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