Undulating numbers: Difference between revisions
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→{{header|J}}: efficiency note
m (→{{header|J}}: presort undul numbers - this could be made more efficient by sorting when the base is chosen) |
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fmt7=: 7{{' '-.~":m&#.inv y}}</syntaxhighlight>
As an aside, undul could have been made more efficient, if speed was a concern, precalculating and sorting the digit pairs when the base was choosen:
<syntaxhighlight lang=J>undul=: {{ m {{ m #. y$"1 n}} (/:~ (<:m)}.(,|."1)2 comb m) }}</syntaxhighlight>
We get:
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