Data commit

Task/Modular-inverse/Action-/modular-inverse.action

@@ -0,0 +1,39 @@
+INT FUNC ModInverse(INT a,b)
+  INT t,nt,r,nr,q,tmp
+
+  IF b<0 THEN b=-b FI
+  IF a<0 THEN a=b-(-a MOD b) FI
+  t=0 nt=1
+  r=b nr=a MOD 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
+    RETURN (-1)
+  FI
+  IF t<0 THEN
+    t==+b
+  FI
+RETURN (t)
+
+PROC Test(INT a,b)
+  INT res
+
+  res=ModInverse(a,b)
+  IF res>=0 THEN
+    PrintF("%I MODINV %I=%I%E",a,b,res)
+  ELSE
+    PrintF("%I MODINV %I has no result%E",a,b)
+  FI
+RETURN
+
+PROC Main()
+  Test(42,2017)
+  Test(40,1)
+  Test(52,-217)
+  Test(-486,217)
+  Test(40,2018)
+RETURN