add inv() to acl_fac

hitonanode · hitonanode · commit 639b71d23008 · 2025-05-12T23:00:20.000+09:00
diff --git a/number/acl_modint.hpp b/number/acl_modint.hpp
@@ -28,5 +28,6 @@ template <typename modint> struct acl_fac {
     }
     modint operator[](int i) const { return facs[i]; }
     modint finv(int i) const { return facinvs[i]; }
+    modint inv(int i) const { return i > 0 ? facinvs[i] * facs[i - 1] : 1; }
 };
 // acl_fac<mint> fac(1000000);

Original file line number	Diff line number	Diff line change
`@@ -28,5 +28,6 @@ template <typename modint> struct acl_fac {`
`28`	`28`	`}`
`29`	`29`	`modint operator[](int i) const { return facs[i]; }`
`30`	`30`	`modint finv(int i) const { return facinvs[i]; }`
	`31`	`+ modint inv(int i) const { return i > 0 ? facinvs[i] * facs[i - 1] : 1; }`
`31`	`32`	`};`
`32`	`33`	`// acl_fac<mint> fac(1000000);`