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id	title	challengeType	forumTopicId	dashedName
595668ca4cfe1af2fb9818d4	Harshad or Niven series	5	302281	harshad-or-niven-series

--description--

The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits.

For example, 42 is a Harshad number as 42 is divisible by (4 + 2) without remainder.

Assume that the series is defined as the numbers in increasing order.

--instructions--

Implement a function to generate successive members of the Harshad sequence.

Use it to return an array with ten members of the sequence, starting with first Harshad number greater than n.

--hints--

isHarshadOrNiven should be a function.

assert(typeof isHarshadOrNiven === 'function');

isHarshadOrNiven(10) should return [12, 18, 20, 21, 24, 27, 30, 36, 40, 42]

assert.deepEqual(isHarshadOrNiven(10), [12, 18, 20, 21, 24, 27, 30, 36, 40, 42]);

isHarshadOrNiven(400) should return [402, 405, 407, 408, 410, 414, 420, 423, 432, 440]

assert.deepEqual(isHarshadOrNiven(400), [402, 405, 407, 408, 410, 414, 420, 423, 432, 440]);

isHarshadOrNiven(1000) should return [1002, 1008, 1010, 1011, 1012, 1014, 1015, 1016, 1017, 1020]

assert.deepEqual(isHarshadOrNiven(1000), [1002, 1008, 1010, 1011, 1012, 1014, 1015, 1016, 1017, 1020]);

--seed--

--seed-contents--

function isHarshadOrNiven(n) {
  const res = [];

  return res;
}

--solutions--

function isHarshadOrNiven(n) {
  function isHarshad(num) {
    let s = 0;
    const nStr = num.toString();
    for (let i = 0; i < nStr.length; ++i) {
      s += parseInt(nStr.charAt(i), 10);
    }
    return n % s === 0;
  }

  const res = [];
  let count = 0;

  while (count < 10) {
    n++;
    if (isHarshad(n)) {
      count++;
      res.push(n);
    }
  }

  return res;
}

1.8 KiB Raw Blame History