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Posted on Oct 22, 2019

Daily Challenge #97 - Greed is Good

#challenge

Greed is a dice game played with five six-sided dice. Your mission, should you choose to accept it, is to score a throw according to these rules. You will always be given an array with five six-sided dice values.

 Three 1's => 1000 points
 Three 6's =>  600 points
 Three 5's =>  500 points
 Three 4's =>  400 points
 Three 3's =>  300 points
 Three 2's =>  200 points
 One   1   =>  100 points
 One   5   =>   50 point

A single die can only be counted once in each roll. For example, a "5" can only count as part of a triplet (contributing to the 500 points) or as a single 50 points, but not both in the same roll.

Example scoring

In some languages, it is possible to mutate the input to the function. This is something that you should never do. If you mutate the input, you will not be able to pass all the tests.

This challenge comes from JulianNicholls on CodeWars, who has licensed redistribution of this challenge under the 2-Clause BSD License!

Want to propose a challenge idea for a future post? Email yo+challenge@dev.to with your suggestions!

Top comments (7)

Julian Nicholls • Oct 22 '19

Hi, Julian here!

There are two subtleties that catch out a great deal of the people who try this on Codewars.

The first is mentioned in this article, don't mutate the input.

The second is shown up by this combination: 3 3 3 3 2
That should score 300, but many people end up incorrectly giving 0 as the score.

Daan Wilmer • Oct 25 '19

What do you mean with "Don't mutate the input"? The variable that is given isn't changed, right?

Julian Nicholls • Oct 25 '19

In some languages on Codewars (Python is the problem here, I think) it is possible to mutate the array that is passed as input. That will guarantee that the test will fail.

Generally it is not good to mutate the input to a function, unless that is the expected behaviour.

Mihail Malo • Oct 23 '19

Why do they give 0?!

Julian Nicholls • Oct 23 '19

The problem comes when there aren't exactly three of a number.

Mihail Malo • Oct 23 '19

I guess that's no more contrived than the solution that would give 600 so that's okay.

erezwanderman • Oct 22 '19

Javascript!

const score = rolls => {
  const rollsOfNum = [1, 2, 3, 4, 5, 6].reduce((p, c) => Object.assign(p, {[c]: rolls.filter(x => x === c).length}), {})
  return (
    (Math.floor(rollsOfNum[1] / 3)) * 1000 +
    (Math.floor(rollsOfNum[6] / 3)) * 600 +
    (Math.floor(rollsOfNum[5] / 3)) * 500 +
    (Math.floor(rollsOfNum[4] / 3)) * 400 +
    (Math.floor(rollsOfNum[3] / 3)) * 300 +
    (Math.floor(rollsOfNum[2] / 3)) * 200 +
    (rollsOfNum[1] % 3) * 100 +
    (rollsOfNum[5] % 3) * 50
  );
};

const testRolls = [
  [5, 1, 3, 4, 1],
  [1, 1, 1, 3, 1],
  [2, 4, 4, 5, 4],
  [1, 1, 1, 1, 1, 1, 1, 1, 1],
  [3, 3, 3, 3, 2],
];
for (const testRoll of testRolls) {
  console.log(testRoll + ': ' + score(testRoll));
}

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Daily Challenge #97 - Greed is Good

Top comments (7)

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