giles
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Test, Build, and Deploy / test-build-deploy (push) Failing after 48s
In-place Fisher-Yates shuffle using:
Random.init 42 deterministic seed
let a = Array.of_list xs
for i = n - 1 downto 1 do reverse iteration
let j = Random.int (i + 1)
let tmp = a.(i) in
a.(i) <- a.(j);
a.(j) <- tmp
done
Sum is invariant under permutation, so the test value (55 for
[1..10] = 1+2+...+10) verifies the shuffle is a valid permutation
regardless of which permutation the seed yields.
Exercises Random.init / Random.int + Array.of_list / to_list /
length / arr.(i) / arr.(i) <- v + downto loop + multi-statement
sequencing within for-body.
33 baseline programs total.
16 lines
300 B
OCaml
16 lines
300 B
OCaml
let shuffle xs =
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Random.init 42;
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let a = Array.of_list xs in
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let n = Array.length a in
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for i = n - 1 downto 1 do
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let j = Random.int (i + 1) in
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let tmp = a.(i) in
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a.(i) <- a.(j);
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a.(j) <- tmp
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done;
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Array.to_list a
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;;
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List.fold_left (+) 0 (shuffle [1;2;3;4;5;6;7;8;9;10])
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