9 lines
291 B
D
9 lines
291 B
D
void main() {
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import std.stdio, std.algorithm, std.range, permutations2;
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enum n = 8;
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n.iota.array.permutations.filter!(p =>
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n.iota.map!(i => p[i] + i).array.sort().uniq.count == n &&
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n.iota.map!(i => p[i] - i).array.sort().uniq.count == n)
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.count.writeln;
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}
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