massively improve performance with dynamic programming

cmd/stirling.go

@@ -19,6 +19,7 @@ package cmd
 import (
 	"fmt"
 	"math/big"
+	"strconv"
 
 	"github.com/spf13/cobra"
 	"scm.dairydemon.net/filifa/mathtools/internal/lib"
@@ -31,13 +32,13 @@ var stirlingBottom string
 var stirlingUnsigned bool
 
 func stirling(cmd *cobra.Command, args []string) {
-	n, ok := new(big.Int).SetString(stirlingTop, 10)
-	if !ok {
+	n, err := strconv.Atoi(stirlingTop)
+	if err != nil {
 		cobra.CheckErr("invalid input " + stirlingTop)
 	}
 
-	k, ok := new(big.Int).SetString(stirlingBottom, 10)
-	if !ok {
+	k, err := strconv.Atoi(stirlingBottom)
+	if err != nil {
 		cobra.CheckErr("invalid input " + stirlingBottom)
 	}