8 lines
409 B
APL
8 lines
409 B
APL
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fromRoman←{
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rmn←(⎕A,⎕A,'*')[(⎕A,⎕UCS 96+⍳26)⍳⍵] ⍝ make input uppercase
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dgt←↑'IVXLCDM' (1 5 10 50 100 500 1000) ⍝ values of roman digits
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~rmn∧.∊⊂dgt[1;]:⎕SIGNAL 11 ⍝ domain error if non-roman input
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map←dgt[2;dgt[1;]⍳rmn] ⍝ map digits to values
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+/map×1-2×(2</map),0 ⍝ subtractive principle
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}
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