Pythagorean triples: Difference between revisions
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(J: the easy implementation) |
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pytr 10000 takes 4 seconds on this laptop, and time to complete grows with square of perimeter, so pytr 1e6 should take a something like 11 hours using this algorithm on this machine. |
pytr 10000 takes 4 seconds on this laptop, and time to complete grows with square of perimeter, so pytr 1e6 should take a something like 11 hours using this algorithm on this machine. |
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A slightly smarter approach: |
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<lang j>trips=:3 :0 |
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'm n'=. |:(#~ 1 = 2 | +/"1)(#~ >/"1),/,"0/~}.i.<.%:y |
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prim=. (#~ 1 = 2 +./@{. |:) (#~ y>:+/"1)m (-&*:,. +:@*,. +&*:) n |
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(,.~ e.&prim) ~./:~;<@(*/~ 1 + y i.@<.@% +/)"1 prim |
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)</lang> |
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usage for trips is the same as for pytr. Thus: |
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<lang j> (# , 1 {. +/) trips 10 |
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0 0 |
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(# , 1 {. +/) trips 100 |
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17 7 |
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(# , 1 {. +/) trips 1000 |
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325 70 |
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(# , 1 {. +/) trips 10000 |
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4858 703 |
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(# , 1 {. +/) trips 100000 |
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64741 7026 |
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(# , 1 {. +/) trips 1000000 |
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808950 70229 |
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(# , 1 {. +/) trips 10000000 |
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9706567 702309</lang> |
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The last line took about 16 seconds. |
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=={{header|Java}}== |
=={{header|Java}}== |
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