18 lines
613 B
D
18 lines
613 B
D
import std.stdio, std.bigint, std.range, std.algorithm, std.conv;
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BigInt leftFact(in uint n) pure nothrow /*@safe*/ {
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BigInt result = 0, factorial = 1;
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foreach (immutable i; 1 .. n + 1) {
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result += factorial;
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factorial *= i;
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}
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return result;
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}
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void main() {
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writeln("First 11 left factorials:\n", 11.iota.map!leftFact);
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writefln("\n20 through 110 (inclusive) by tens:\n%(%s\n%)",
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iota(20, 111, 10).map!leftFact);
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writefln("\nDigits in 1,000 through 10,000 by thousands:\n%s",
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iota(1_000, 10_001, 1_000).map!(i => i.leftFact.text.length));
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}
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