Class DensePoly

java.lang.Object
it.unimi.di.prog2.h10.DensePoly
public class DensePoly extends Object
DensePolys are immutable polynomials with integer coefficients.

A typical Poly is \( p = c_0 + c_1 x + c_2 x^2 + \cdots + c_n x^n \).

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final int[]
    coefficient
    The array of coefficients, the coeff[i] is the coefficient of \( x^i \).

  • Constructor Summary

    Constructors
    Constructor
    Description
    DensePoly()
    Initializes this to be the zero polynomial, that is \( p = 0 \).
    DensePoly(int[] coefficient)
    Initializes a polynomial given an array of coefficients.
    DensePoly(int c, int n)
    Initializes this to be the polynomial \(p = cx^n\).

  • Method Summary

    Modifier and Type
    Method
    Description
    DensePoly
    add(DensePoly q)
    Performs polynomial addition.
    int
    coeff(int d)
    Returns the coefficient of the term of given exponent.
    int
    degree()
    Returns the degree of this polynomial.
    boolean
    isZero()
    Checks whether this polynomial is the zero polynomial.
    DensePoly
    minus()
    Returns the negate polynomial.
    DensePoly
    mul(DensePoly q)
    Performs polynomial multiplication.
    DensePoly
    sub(DensePoly q)
    Performs polynomial subtraction.

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • coefficient

      private final int[] coefficient
      The array of coefficients, the coeff[i] is the coefficient of \( x^i \).

  • Constructor Details

    • DensePoly

      public DensePoly()
      Initializes this to be the zero polynomial, that is \( p = 0 \).

    • DensePoly

      public DensePoly(int c, int n) throws IllegalArgumentException
      Initializes this to be the polynomial \(p = cx^n\).
      Parameters:
      c - the coefficient.
      n - the degree.
      Throws:
      IllegalArgumentException - if n < 0.

    • DensePoly

      public DensePoly(int[] coefficient)
      Initializes a polynomial given an array of coefficients.

      The coefficient array can have trailing zeros, they will not be considered in the representation of the polynomial.

      Parameters:
      coefficient - the array of coefficients.

  • Method Details

    • degree

      public int degree()
      Returns the degree of this polynomial.

      The degree is defined as the largest exponent with a non-zero coefficient.

      Returns:
      the largest exponent with a non-zero coefficient.
      Throws:
      IllegalStateException - if this is the zero polynomial.

    • coeff

      public int coeff(int d)
      Returns the coefficient of the term of given exponent.
      Parameters:
      d - the exponent of the term to consider.
      Returns:
      the coefficient of the considered term.

    • isZero

      public boolean isZero()
      Checks whether this polynomial is the zero polynomial.
      Returns:
      true if this polynomial is the zero polynomial, false otherwise.

    • add

      public DensePoly add(DensePoly q) throws NullPointerException
      Performs polynomial addition.

      If \( p \) is this polynomial, returns \( p + q \).

      Parameters:
      q - the polynomial to add to this one.
      Returns:
      the sum among this and the given polynomial.
      Throws:
      NullPointerException - if q is null.

    • mul

      public DensePoly mul(DensePoly q) throws NullPointerException
      Performs polynomial multiplication.

      If \( p \) is this polynomial, returns \( p q \).

      Parameters:
      q - the polynomial to multiply by this one.
      Returns:
      the product among this and the given polynomial.
      Throws:
      NullPointerException - if q is null.

    • sub

      public DensePoly sub(DensePoly q) throws NullPointerException
      Performs polynomial subtraction.

      If \( p \) is this polynomial, returns \( p - q \).

      Parameters:
      q - the polynomial to subtract from this one.
      Returns:
      the subtraction among this and the given polynomial.
      Throws:
      NullPointerException - if q is null.

    • minus

      public DensePoly minus()
      Returns the negate polynomial.

      If \( p \) is this polynomial, returns \( -p \).

      Returns:
      this polynomial multiplied by \( -1 \).