45 lines
1.2 KiB
Plaintext
45 lines
1.2 KiB
Plaintext
>function hailstone (n) ...
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$ v=[n];
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$ repeat
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$ if mod(n,2) then n=3*n+1;
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$ else n=n/2;
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$ endif;
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$ v=v|n;
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$ until n==1;
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$ end;
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$ return v;
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$ endfunction
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>hailstone(27), length(%)
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[ 27 82 41 124 62 31 94 47 142 71 214 107 322 161 484 242
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121 364 182 91 274 137 412 206 103 310 155 466 233 700
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350 175 526 263 790 395 1186 593 1780 890 445 1336 668
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334 167 502 251 754 377 1132 566 283 850 425 1276 638 319
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958 479 1438 719 2158 1079 3238 1619 4858 2429 7288 3644
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1822 911 2734 1367 4102 2051 6154 3077 9232 4616 2308 1154
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577 1732 866 433 1300 650 325 976 488 244 122 61 184 92
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46 23 70 35 106 53 160 80 40 20 10 5 16 8 4 2 1 ]
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112
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>function hailstonelength (n) ...
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$ v=zeros(1,n);
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$ v[1]=4; v[2]=2;
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$ loop 3 to n;
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$ count=1;
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$ n=#;
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$ repeat
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$ if mod(n,2) then n=3*n+1;
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$ else n=n/2;
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$ endif;
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$ if n<=cols(v) and v[n] then
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$ v[#]=v[n]+count;
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$ break;
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$ endif;
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$ count=count+1;
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$ end;
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$ end;
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$ return v;
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$ endfunction
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>h=hailstonelength(100000);
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>ex=extrema(h); ex[3], ex[4]
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351
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77031
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