class Factorial_memoized {
  static memoList = [ ( 0G ) : 1 , ( 1G ) : 1 ]
  static iterative ( BigInteger n ) {
    if ( n < 0 ) { throw new FactorialIllegalArgumentException ( 'Parameter must be a non-negative integer.' ) }
    if ( memoList[n] ) { return memoList[n] }
    def total = 1G
    if ( n > 1 ) { for ( i in 2G..n ) { total *= i } }
    memoList[n] = total
  }
  static iterative ( Integer n ) { iterative ( new BigInteger ( n.toString ( ) ) ) }
  static iterative ( Long n ) { iterative ( new BigInteger ( n.toString ( ) ) ) }
  static recursive ( BigInteger n ) {
    if ( n < 0 ) { throw new FactorialIllegalArgumentException ( 'Parameter must be a non-negative integer.' ) }
    if ( memoList[n] ) { return memoList[n] }    
    memoList[n] = n <= 1 ? 1 : n * recursive ( n - 1 )
  }
  static recursive ( Integer n ) { recursive ( new BigInteger ( n.toString ( ) ) ) }
  static recursive ( Long n ) { recursive ( new BigInteger ( n.toString ( ) ) ) }
  static tailRecursive ( BigInteger n ) {
    if ( n < 0 ) { throw new FactorialIllegalArgumentException ( 'Parameter must be a non-negative integer.' ) }
    if ( memoList[n] ) { return memoList[n] }
    def iterate
    iterate = { i , result -> i < 2 ? 1 : iterate ( i - 1 , result * i ) }
    memoList[n] = iterate ( n , 1 )
  }
  static tailRecursive ( Integer n ) { tailRecursive ( new BigInteger ( n.toString ( ) ) ) }
  static tailRecursive ( Long n ) { tailRecursive ( new BigInteger ( n.toString ( ) ) ) }
}