MCD in Dart w/ tests

mcd.dart

import 'package:flutter_test/flutter_test.dart';

int mcd(int a, int b) => b == 0 ? a.abs() : mcd(b, a % b);

void main() {
  group('MCD Tests', () {
    test('positive numbers', () {
      expect(mcd(48, 18), equals(6));
      expect(mcd(56, 98), equals(14));
      expect(mcd(101, 103), equals(1));
      expect(mcd(54, 24), equals(6));
      expect(mcd(81, 27), equals(27));
      expect(mcd(100, 25), equals(25));
      expect(mcd(49, 7), equals(7));
      expect(mcd(77, 11), equals(11));
      expect(mcd(91, 13), equals(13));
      expect(mcd(121, 11), equals(11));
    });

    test('negative numbers', () {
      expect(mcd(-48, 18), equals(6));
      expect(mcd(56, -98), equals(14));
      expect(mcd(-101, -103), equals(1));
      expect(mcd(-54, 24), equals(6));
      expect(mcd(81, -27), equals(27));
      expect(mcd(-100, 25), equals(25));
      expect(mcd(-49, -7), equals(7));
      expect(mcd(77, -11), equals(11));
      expect(mcd(-91, 13), equals(13));
      expect(mcd(-121, -11), equals(11));
    });

    test('zero', () {
      expect(mcd(0, 18), equals(18));
      expect(mcd(56, 0), equals(56));
      expect(mcd(0, 0), equals(0));
      expect(mcd(0, 1), equals(1));
      expect(mcd(1, 0), equals(1));
      expect(mcd(0, -1), equals(1));
      expect(mcd(-1, 0), equals(1));
      expect(mcd(0, 100), equals(100));
      expect(mcd(100, 0), equals(100));
      expect(mcd(0, -100), equals(100));
    });

    test('same numbers', () {
      expect(mcd(20, 20), equals(20));
      expect(mcd(-20, -20), equals(20));
      expect(mcd(100, 100), equals(100));
      expect(mcd(-100, -100), equals(100));
      expect(mcd(1, 1), equals(1));
      expect(mcd(-1, -1), equals(1));
      expect(mcd(50, 50), equals(50));
      expect(mcd(-50, -50), equals(50));
      expect(mcd(75, 75), equals(75));
      expect(mcd(-75, -75), equals(75));
    });

    test('one', () {
      expect(mcd(1, 18), equals(1));
      expect(mcd(56, 1), equals(1));
      expect(mcd(1, 1), equals(1));
      expect(mcd(1, 100), equals(1));
      expect(mcd(100, 1), equals(1));
      expect(mcd(1, -18), equals(1));
      expect(mcd(-56, 1), equals(1));
      expect(mcd(-1, 1), equals(1));
      expect(mcd(1, -100), equals(1));
      expect(mcd(-100, 1), equals(1));
    });

    test('large numbers', () {
      expect(mcd(123456, 789012), equals(12));
      expect(mcd(987654321, 123456789), equals(9));
      expect(mcd(1000000000, 500000000), equals(500000000));
      expect(mcd(999999937, 999999937), equals(999999937));
      expect(mcd(2147483647, 2147483647), equals(2147483647));
      expect(mcd(1000000007, 1000000009), equals(1));
      expect(mcd(4294967295, 2147483647), equals(1));
    });

    test('random cases', () {
      expect(mcd(15, 25), equals(5));
      expect(mcd(35, 10), equals(5));
      expect(mcd(40, 60), equals(20));
      expect(mcd(70, 105), equals(35));
      expect(mcd(90, 150), equals(30));
      expect(mcd(120, 180), equals(60));
      expect(mcd(200, 300), equals(100));
      expect(mcd(250, 375), equals(125));
      expect(mcd(360, 540), equals(180));
      expect(mcd(450, 675), equals(225));
    });
  });
}