44-prize-draw.js

// To participate in a prize draw each one gives his/her firstname.
// Each letter of a firstname has a value which is its rank in the English alphabet.
// A and a have rank 1, B and b rank 2 and so on.
// The length of the firstname is added to the sum of these ranks hence a number n.
// An array of random weights is linked to the firstnames and each n is multiplied
// by its corresponding weight to get what they call a winning number.

// Example: names: COLIN,AMANDBA,AMANDAB,CAROL,PauL,JOSEPH weights: [1, 4, 4, 5, 2, 1]

// PAUL -> n = length of firstname + 16 + 1 + 21 + 12 = 4 + 50 -> 54
// The weight associated with PAUL is 2 so Paul's winning number is 54 * 2 = 108.

// Now one can sort the firstnames in decreasing order of the winning numbers.
// When two people have the same winning number sort them alphabetically by their firstnames.

// #Task:
// parameters: st a string of firstnames, we an array of weights, n a rank
// return: the firstname of the participant whose rank is n (ranks are numbered from 1)
// #Example: names: COLIN,AMANDBA,AMANDAB,CAROL,PauL,JOSEPH weights: [1, 4, 4, 5, 2, 1] n: 4
// The function should return: PauL
// #Note: If st is empty return "No participants".
// If n is greater than the number of participants then return "Not enough participants".

export default (st, we, n) => {
  if (!st.length) return 'No participants';
  const arrayOfCosts = st.split(',')
    .reduce((acc, e, ind) =>
      [...acc, [e, (e.split('').reduce((a, s) => (a + s.toLowerCase().charCodeAt()) - 96, 0) + e.length) * we[ind]]], [])
    .sort(([aName, aCost], [bName, bCost]) => {
      if ((bCost - aCost) !== 0) return bCost - aCost;
      if (aName < bName) return -1;
      if (aName > bName) return 1;
      return 0;
    });
  return arrayOfCosts[n - 1] ? arrayOfCosts[n - 1][0] : 'Not enough participants';
};