Class Factorial

java.lang.Object
topics.divideconquer.factorial.Factorial
public class Factorial extends Object

Factorial Calculation

Demonstrates both the iterative and recursive paradigms for computing the factorial of a non-negative integer (N!).

*

The Integer Overflow Trap

Factorial functions grow explosively.

  • Using standard 32-bit int, the maximum computable value is 12!
  • At 13!, the value exceeds 2.14 billion and causes a silent arithmetic overflow.
  • By upgrading to 64-bit long, this implementation safely computes up to 20!
For values strictly greater than 20!, Java's BigInteger class must be used.

Author:
vicegd

  • Constructor Details

    • Factorial

      public Factorial()

  • Method Details

    • factorialIterative

      public long factorialIterative(int n)
      Iterative implementation using a linear accumulator.
      • Time Complexity: O(N)
      • Space Complexity: O(1)
      Parameters:
      n - A non-negative integer up to 20.
      Returns:
      The factorial of N.
      Throws:
      IllegalArgumentException - if N is negative.

    • factorialRecursive

      public long factorialRecursive(int n)
      Recursive implementation demonstrating Divide and Conquer by Subtraction.
      • Time Complexity: O(N)
      • Space Complexity: O(N) due to the execution call stack.
      Parameters:
      n - A non-negative integer up to 20.
      Returns:
      The factorial of N.
      Throws:
      IllegalArgumentException - if N is negative.