Fix division

1 files changed, 5 insertions, 3 deletions

diff --git a/zmodn.h b/zmodn.h
index fdb1ee6..890fb0e 100644
--- a/zmodn.h
+++ b/zmodn.h
@@ -40,13 +40,15 @@ public:
         bool operator!=(const Zmod& z) const { return value != z.value; }
 
         std::optional<Zmod> inverse() const {
-                auto [g, a, _] = extended_gcd(value, N);
+                auto [g, a, b] = extended_gcd(value, N);
                 return g == 1 ? Zmod(a) : std::optional<Zmod>{};
         }
 
         std::optional<Zmod> operator/(const Zmod& d) const {
-                auto i = d.inverse();
-                return i ? (*this) * i.value() : i;
+                auto [g, x, y] = extended_gcd(value, d.toint());
+                auto [a, b] = std::pair<Zmod, Zmod>{value / g, d.toint() / g};
+                auto i = b.inverse();
+                return i ? a * i.value() : i;
         }
 
         std::optional<Zmod> operator/=(const Zmod& d) {