Modular inverse: Difference between revisions
Add Draco
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=={{header|Delphi}}==
See [[#Pascal]].
=={{header|Draco}}==
<lang draco>proc mulinv(int a, b) int:
int t, nt, r, nr, q, tmp;
if b<0 then b := -b fi;
if a<0 then a := b - (-a % b) fi;
t := 0; nt := 1; r := b; nr := a % b;
while nr /= 0 do
q := r / nr;
tmp := nt; nt := t - q*nt; t := tmp;
tmp := nr; nr := r - q*nr; r := tmp
od;
if r>1 then -1
elif t<0 then t+b
else t
fi
corp
proc show(int a, b) void:
int mi;
mi := mulinv(a, b);
if mi>=0
then writeln(a:5, ", ", b:5, " -> ", mi:5)
else writeln(a:5, ", ", b:5, " -> no inverse")
fi
corp
proc main() void:
show(42, 2017);
show(40, 1);
show(52, -217);
show(-486, 217);
show(40, 2018)
corp</lang>
{{out}}
<pre> 42, 2017 -> 1969
40, 1 -> 0
52, -217 -> 96
-486, 217 -> 121
40, 2018 -> no inverse</pre>
=={{header|EchoLisp}}==
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