Function bigFactorial

project_euler/problem_20/problem20.go:29–37

bigFactorial returns the factorial of n as a big.Int Use big package to handle large numbers

(n int)

// bigFactorial returns the factorial of n as a big.Int
// Use big package to handle large numbers
func bigFactorial(n int) *big.Int {
	if n < 0 {
		return big.NewInt(0)
	}
	if n == 0 {
		return big.NewInt(1)
	}
	return big.NewInt(0).Mul(big.NewInt(int64(n)), bigFactorial(n-1))
}