mirror of https://github.com/janet-lang/janet
19 lines
468 B
Plaintext
19 lines
468 B
Plaintext
(defn sum3
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"Solve the 3SUM problem in O(n^2) time."
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[s]
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(def tab @{})
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(def solutions @{})
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(def len (length s))
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(for k 0 len
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(put tab (s k) k))
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(for i 0 len
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(for j 0 len
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(def k (get tab (- 0 (s i) (s j))))
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(when (and k (not= k i) (not= k j) (not= i j))
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(put solutions {i true j true k true} true))))
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(map keys (keys solutions)))
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(def arr @[2 4 1 3 8 7 -3 -1 12 -5 -8])
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(printf "3sum of %P: " arr)
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(printf "%P\n" (sum3 arr))
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