AdventOfCode2023/UPolynomial.pas

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{
Solutions to the Advent Of Code.
Copyright (C) 2024 Stefan Müller
This program is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.
}
unit UPolynomial;
{$mode ObjFPC}{$H+}
interface
uses
Classes, SysUtils, UBigInt;
type
TInt64Array = array of Int64;
{ TBigIntPolynomial }
TBigIntPolynomial = object
private
FCoefficients: array of TBigInt;
public
function CalcValueAt(const AX: Int64): TBigInt;
function IsEqualTo(const AOther: TBigIntPolynomial): Boolean;
class function Create(const ACoefficients: array of TBigInt): TBigIntPolynomial; static;
end;
{ Operators }
operator = (const A, B: TBigIntPolynomial): Boolean;
operator <> (const A, B: TBigIntPolynomial): Boolean;
implementation
{ TBigIntPolynomial }
function TBigIntPolynomial.CalcValueAt(const AX: Int64): TBigInt;
var
i: Integer;
begin
Result := TBigInt.Zero;
for i := High(FCoefficients) downto 0 do
Result := Result * AX + FCoefficients[i];
end;
function TBigIntPolynomial.IsEqualTo(const AOther: TBigIntPolynomial): Boolean;
var
i: Integer;
begin
if Length(FCoefficients) = Length(AOther.FCoefficients) then
begin
Result := True;
for i := 0 to Length(FCoefficients) - 1 do
if FCoefficients[i] <> AOther.FCoefficients[i] then
begin
Result := False;
Break;
end;
end
else
Result := False;
end;
class function TBigIntPolynomial.Create(const ACoefficients: array of TBigInt): TBigIntPolynomial;
var
high, i: integer;
begin
high := 1;
for i := Length(ACoefficients) - 1 downto 1 do
if ACoefficients[i] <> 0 then
begin
high := i;
Break;
end;
SetLength(Result.FCoefficients, high + 1);
for i := 0 to high do
Result.FCoefficients[i] := ACoefficients[i];
end;
{ Operators }
operator = (const A, B: TBigIntPolynomial): Boolean;
begin
Result := A.IsEqualTo(B);
end;
operator <> (const A, B: TBigIntPolynomial): Boolean;
begin
Result := not A.IsEqualTo(B);
end;
end.