dist-javascript-algorithms-and-data-structures/dist/algorithms/sets/combinations/__test__/combineWithoutRepetitions.test.js

Algorithms and data-structures implemented on JavaScript

"use strict";

var _combineWithoutRepetitions = _interopRequireDefault(require("../combineWithoutRepetitions"));

var _factorial = _interopRequireDefault(require("../../../math/factorial/factorial"));

var _pascalTriangle = _interopRequireDefault(require("../../../math/pascal-triangle/pascalTriangle"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

describe('combineWithoutRepetitions', () => {
  it('should combine string without repetitions', () => {
    expect((0, _combineWithoutRepetitions.default)(['A', 'B'], 3)).toEqual([]);
    expect((0, _combineWithoutRepetitions.default)(['A', 'B'], 1)).toEqual([['A'], ['B']]);
    expect((0, _combineWithoutRepetitions.default)(['A'], 1)).toEqual([['A']]);
    expect((0, _combineWithoutRepetitions.default)(['A', 'B'], 2)).toEqual([['A', 'B']]);
    expect((0, _combineWithoutRepetitions.default)(['A', 'B', 'C'], 2)).toEqual([['A', 'B'], ['A', 'C'], ['B', 'C']]);
    expect((0, _combineWithoutRepetitions.default)(['A', 'B', 'C'], 3)).toEqual([['A', 'B', 'C']]);
    expect((0, _combineWithoutRepetitions.default)(['A', 'B', 'C', 'D'], 3)).toEqual([['A', 'B', 'C'], ['A', 'B', 'D'], ['A', 'C', 'D'], ['B', 'C', 'D']]);
    expect((0, _combineWithoutRepetitions.default)(['A', 'B', 'C', 'D', 'E'], 3)).toEqual([['A', 'B', 'C'], ['A', 'B', 'D'], ['A', 'B', 'E'], ['A', 'C', 'D'], ['A', 'C', 'E'], ['A', 'D', 'E'], ['B', 'C', 'D'], ['B', 'C', 'E'], ['B', 'D', 'E'], ['C', 'D', 'E']]);
    const combinationOptions = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'];
    const combinationSlotsNumber = 4;
    const combinations = (0, _combineWithoutRepetitions.default)(combinationOptions, combinationSlotsNumber);
    const n = combinationOptions.length;
    const r = combinationSlotsNumber;
    const expectedNumberOfCombinations = (0, _factorial.default)(n) / ((0, _factorial.default)(r) * (0, _factorial.default)(n - r));
    expect(combinations.length).toBe(expectedNumberOfCombinations); // This one is just to see one of the way of Pascal's triangle application.

    expect(combinations.length).toBe((0, _pascalTriangle.default)(n)[r]);
  });
});