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Merge pull request #545 from felixr/master

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Revert my buggy hybrid sort
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Calvin Rose 2021-01-03 16:39:23 -06:00 committed by GitHub
commit 81f62b246c
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1 changed files with 21 additions and 32 deletions
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53
src/boot/boot.janet
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@ -774,45 +774,34 @@
a
(if (not= (> b a) (> b c)) b c)))
(defn- insertion-sort [a lo hi by]
(for i (+ lo 1) (+ hi 1)
(def temp (in a i))
(var j (- i 1))
(while (and (>= j lo) (by temp (in a j)))
(set (a (+ j 1)) (in a j))
(-- j))
(set (a (+ j 1)) temp))
(defn sort-help [a lo hi by]
(when (< lo hi)
(def pivot
(median-of-three (in a hi) (in a lo)
(in a (math/floor (/ (+ lo hi) 2)))))
(var left lo)
(var right hi)
(while true
(while (by (in a left) pivot) (++ left))
(while (by pivot (in a right)) (-- right))
(when (<= left right)
(def tmp (in a left))
(set (a left) (in a right))
(set (a right) tmp)
(++ left)
(-- right))
(if (>= left right) (break)))
(sort-help a lo right by)
(sort-help a left hi by))
a)
(defn sort
"Sort an array in-place. Uses quick-sort and is not a stable sort."
[a &opt by]
(default by <)
(def stack @[[0 (- (length a) 1)]])
(while (not (empty? stack))
(def [lo hi] (array/pop stack))
(when (< lo hi)
(when (< (- hi lo) 32) (insertion-sort a lo hi by) (break))
(def pivot (median-of-three (in a hi) (in a lo) (in a (math/floor (/ (+ lo hi) 2)))))
(var left lo)
(var right hi)
(while true
(while (by (in a left) pivot) (++ left))
(while (by pivot (in a right)) (-- right))
(when (<= left right)
(def tmp (in a left))
(set (a left) (in a right))
(set (a right) tmp)
(++ left)
(-- right))
(if (>= left right) (break)))
(array/push stack [lo right])
(array/push stack [left hi])))
a)
(sort-help a 0 (- (length a) 1) (or by <)))
(undef median-of-three)
(undef insertion-sort)
(undef sort-help)
(defn sort-by
`Returns a new sorted array that compares elements by invoking