33 lines
823 B
D
33 lines
823 B
D
import std.array : uninitializedArray;
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import std.bigint;
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import std.stdio : writeln, writefln;
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auto bellTriangle(int n) {
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auto tri = uninitializedArray!(BigInt[][])(n);
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foreach (i; 0..n) {
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tri[i] = uninitializedArray!(BigInt[])(i);
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tri[i][] = BigInt(0);
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}
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tri[1][0] = 1;
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foreach (i; 2..n) {
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tri[i][0] = tri[i - 1][i - 2];
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foreach (j; 1..i) {
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tri[i][j] = tri[i][j - 1] + tri[i - 1][j - 1];
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}
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}
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return tri;
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}
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void main() {
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auto bt = bellTriangle(51);
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writeln("First fifteen and fiftieth Bell numbers:");
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foreach (i; 1..16) {
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writefln("%2d: %d", i, bt[i][0]);
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}
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writeln("50: ", bt[50][0]);
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writeln;
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writeln("The first ten rows of Bell's triangle:");
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foreach (i; 1..11) {
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writeln(bt[i]);
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}
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}
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