54 lines
965 B
Plaintext
54 lines
965 B
Plaintext
implement Execlib;
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include "sys.m"; sys: Sys;
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include "draw.m";
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Execlib: module {
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init: fn(ctxt: ref Draw->Context, args: list of string);
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hailstone: fn(i: big): list of big;
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};
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init(nil: ref Draw->Context, nil: list of string)
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{
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sys = load Sys Sys->PATH;
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seq := hailstone(big 27);
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l := len seq;
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sys->print("hailstone(27): ");
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for(i := 0; i < 4; i++) {
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sys->print("%bd, ", hd seq);
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seq = tl seq;
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}
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sys->print("⋯");
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while(len seq > 4)
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seq = tl seq;
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while(seq != nil) {
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sys->print(", %bd", hd seq);
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seq = tl seq;
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}
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sys->print(" (length %d)\n", l);
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max := 1;
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maxn := big 1;
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for(n := big 2; n < big 100000; n++) {
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cur := len hailstone(n);
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if(cur > max) {
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max = cur;
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maxn = n;
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}
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}
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sys->print("hailstone(%bd) has length %d\n", maxn, max);
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}
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hailstone(i: big): list of big
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{
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if(i == big 1)
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return big 1 :: nil;
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if(i % big 2 == big 0)
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return i :: hailstone(i / big 2);
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return i :: hailstone(big 3 * i + big 1);
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}
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