Move fact/rfact/small_inv to combinatorics.hpp

Author: adamant-pwn

cp-algo/math/combinatorics.hpp

@@ -3,6 +3,48 @@
 #include "common.hpp"
 #include <cassert>
 namespace cp_algo::math {
+    // fact/rfact/small_inv are caching
+    // Beware of usage with dynamic mod
+    template<typename T>
+    T fact(int n) {
+        static std::vector<T> F(maxn);
+        static bool init = false;
+        if(!init) {
+            F[0] = T(1);
+            for(int i = 1; i < maxn; i++) {
+                F[i] = F[i - 1] * T(i);
+            }
+            init = true;
+        }
+        return F[n];
+    }
+    // Only works for modint types
+    template<typename T>
+    T rfact(int n) {
+        static std::vector<T> F(maxn);
+        static bool init = false;
+        if(!init) {
+            int t = std::min<int64_t>(T::mod(), maxn) - 1;
+            F[t] = T(1) / fact<T>(t);
+            for(int i = t - 1; i >= 0; i--) {
+                F[i] = F[i + 1] * T(i + 1);
+            }
+            init = true;
+        }
+        return F[n];
+    }
+    template<typename T>
+    T small_inv(int n) {
+        static std::vector<T> F(maxn);
+        static bool init = false;
+        if(!init) {
+            for(int i = 1; i < maxn; i++) {
+                F[i] = rfact<T>(i) * fact<T>(i - 1);
+            }
+            init = true;
+        }
+        return F[n];
+    }
     template<typename T>
     T binom_large(T n, int r) {
         assert(r < maxn);

cp-algo/math/common.hpp

@@ -29,47 +29,5 @@ namespace cp_algo::math {
     T bpow(T const& x, int64_t n) {
         return bpow(x, n, T(1));
     }
-    // fact/rfact/small_inv are caching
-    // Beware of usage with dynamic mod
-    template<typename T>
-    T fact(int n) {
-        static std::vector<T> F(maxn);
-        static bool init = false;
-        if(!init) {
-            F[0] = T(1);
-            for(int i = 1; i < maxn; i++) {
-                F[i] = F[i - 1] * T(i);
-            }
-            init = true;
-        }
-        return F[n];
-    }
-    // Only works for modint types
-    template<typename T>
-    T rfact(int n) {
-        static std::vector<T> F(maxn);
-        static bool init = false;
-        if(!init) {
-            int t = std::min<int64_t>(T::mod(), maxn) - 1;
-            F[t] = T(1) / fact<T>(t);
-            for(int i = t - 1; i >= 0; i--) {
-                F[i] = F[i + 1] * T(i + 1);
-            }
-            init = true;
-        }
-        return F[n];
-    }
-    template<typename T>
-    T small_inv(int n) {
-        static std::vector<T> F(maxn);
-        static bool init = false;
-        if(!init) {
-            for(int i = 1; i < maxn; i++) {
-                F[i] = rfact<T>(i) * fact<T>(i - 1);
-            }
-            init = true;
-        }
-        return F[n];
-    }
 }
 #endif // CP_ALGO_MATH_COMMON_HPP