required-data-i.js

/**
 * http://www.codewars.com/kata/required-data-i
 *
 Description:

 We need a function count_sel() that receives an array or list of integers (positive and negative) and may
 give us the following information in the order and structure presented bellow:

 [(1), (2), (3), [[(4)], 5]]

 (1) - Total amount of received integers.

 (2) - Total amount of different values the array has.

 (3) - Total amount of values that occur only once.

 (4) and (5) both in a list

 (4) - It is (or they are) the element(s) that has (or have) the maximum occurrence. If there are more than
 one, the elements should be sorted (by their value obviously)

 (5) - Maximum occurrence of the integer(s)

 Let's see some cases

 ____ count_sel([-3, -2, -1, 3, 4, -5, -5, 5, -1, -5]) ----> [10, 7, 5, [[-5], 3]]

 (1) - The list has ten elements (10 numbers)

 (2) - We have seven different values: -5, -3, -2, -1, 3, 4, 5 (7 values)

 (3) - The numbers that occur only once: -3, -2, 3, 4, 5 (5 values)

 (4) and (5) - The number -5 occurs three times (3 occurrences)

 ____ count_sel([4, 4, 2, -3, 1, 4, 3, 2, 0, -5, 2, -2, -2, -5]) ----> [14, 8, 4, [[2, 4], 3]]

 Enjoy it and happy coding!!


 *
 */

let tests = require('./lib/framework.js');
let Test = tests.Test, describe = tests.describe, it = tests.it, before = tests.before, after = tests.after;

function countSel(data) {
    const freq = {};
    const pairs = [];
    let maxCount = 0;

    data.forEach(x => {
        if (!freq[x]) freq[x] = 0;
        freq[x]++;
    });

    for (let k in freq) {
        if (maxCount < freq[k]) maxCount = freq[k];
        pairs.push({ value: k, count: freq[k] });
    }

    const result = [data.length, pairs.length, pairs.filter(x => x.count === 1).length];

    result.push([
        pairs.filter(x => x.count === maxCount).map(x => +x.value).sort((a, b) => a - b),
        maxCount
    ]);

    return result;
}

describe("Example Tests", function(){
    it("Simple Cases", function(){
        Test.assertSimilar(countSel([-3, -2, -1, 3, 4, -5, -5, 5, -1, -5]), [10, 7, 5, [[-5], 3]]);
        Test.assertSimilar(countSel([5, -1, 1, -1, -2, 5, 0, -2, -5, 3]), [10, 7, 4, [[-2, -1, 5], 2]]);
        Test.assertSimilar(countSel([-2, 4, 4, -2, -2, -1, 3, 5, -5, 5]), [10, 6, 3, [[-2], 3]]);
        Test.assertSimilar(countSel([4, -5, 1, -5, 2, 4, -1, 4, -1, 1]), [10, 5, 1, [[4], 3]]);
        Test.assertSimilar(countSel([4, 4, 2, -3, 1, 4, 3, 2, 0, -5, 2, -2, -2, -5]), [14, 8, 4, [[2, 4], 3]]);
    });
});