giles
ca34cede88
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Test, Build, and Deploy / test-build-deploy (push) Failing after 21s
Right-to-left monotonic stack for next-greater-element:
for i = n - 1 downto 0 do
while (match !stack with [] -> false | h :: _ -> h <= arr.(i)) do
stack := List.tl !stack
done;
(match !stack with
| [] -> res.(i) <- -1
| h :: _ -> res.(i) <- h);
stack := arr.(i) :: !stack
done
For [4; 5; 2; 25; 7; 8; 1; 30; 12]:
results: [5; 25; 25; 30; 8; 30; 30; -1; -1]
sum of non-negative = 5+25+25+30+8+30+30 = 153
Tests stack as ref list with match-driven peek, match-as-bool in
while-guard, inline parenthesized match driving <-.
169 baseline programs total.
24 lines
545 B
OCaml
24 lines
545 B
OCaml
let next_greater arr =
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let n = Array.length arr in
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let res = Array.make n (-1) in
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let stack = ref [] in
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for i = n - 1 downto 0 do
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while (match !stack with [] -> false | h :: _ -> h <= arr.(i)) do
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stack := List.tl !stack
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done;
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(match !stack with
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| [] -> res.(i) <- -1
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| h :: _ -> res.(i) <- h);
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stack := arr.(i) :: !stack
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done;
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res
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;;
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let r = next_greater [| 4; 5; 2; 25; 7; 8; 1; 30; 12 |] in
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let sum = ref 0 in
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for i = 0 to Array.length r - 1 do
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if r.(i) >= 0 then sum := !sum + r.(i)
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done;
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!sum
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