28 lines
781 B
D
28 lines
781 B
D
import std.stdio, std.bigint, std.range, std.algorithm;
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auto binomialCoeff(in uint n, in uint k) pure nothrow {
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BigInt result = 1;
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foreach (immutable i; 1 .. k + 1)
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result = result * (n - i + 1) / i;
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return result;
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}
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auto pascalUpp(in uint n) pure nothrow {
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return n.iota.map!(i => n.iota.map!(j => binomialCoeff(j, i)));
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}
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auto pascalLow(in uint n) pure nothrow {
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return n.iota.map!(i => n.iota.map!(j => binomialCoeff(i, j)));
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}
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auto pascalSym(in uint n) pure nothrow {
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return n.iota.map!(i => n.iota.map!(j => binomialCoeff(i + j, i)));
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}
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void main() {
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enum n = 5;
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writefln("Upper:\n%(%(%2d %)\n%)", pascalUpp(n));
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writefln("\nLower:\n%(%(%2d %)\n%)", pascalLow(n));
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writefln("\nSymmetric:\n%(%(%2d %)\n%)", pascalSym(n));
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}
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