metaory · June 10, 2022 14:53
diff --git a/replace-wildcard-with-non-repeating.js b/replace-wildcard-with-non-repeating.js
 /*
 Rick is a fan of logic-based games. However, he is bored of the classic ones, like Sudoku and Mastermind, since he has solved so many of them. Recently he found a new game in which one is given a string with some question marks in it. The objective is to replace all of the question marks with letters (one letter per question mark) in such a way that no letter appears next to another letter of the same kind.

 Write a function:

 function solution(riddle);

 that, given a string riddle, returns a copy of the string with all of the question marks replaced by lowercase letters (a−z) in such a way that the same letters do not occur next to each other. The result can be any of the possible answers as long as it fulfils the above requirements.

 Examples:

 1. Given riddle = "ab?ac?", your function might return "abcaca". Some other possible results are "abzacd", "abfacf".

 2. Given riddle = "rd?e?wg??", your function might return "rdveawgab".

 3. Given riddle = "????????", your function might return "codility".

 Write an efficient algorithm for the following assumptions:

 the length of the string is within the range [1..100,000];
 string riddle consists only of lowercases letters (a − z) or '?';
 it is always possible to turn string 'riddle' into a string without two identical consecutive letters.
 */

 const { log, table, clear } = console
 clear()

 const CHARECTERS = 'abcdefghijklmnopqrstuvwxyz'
 const randomChar = () => CHARECTERS[Math.floor(Math.random() * CHARECTERS.length)]
 const replaceWildcard = (pre, nex) => {
  const potential = randomChar()
  if ([pre, nex].includes(potential)) {
    return replaceWildcard(pre, nex)
  } else {
    return potential
  }
 }

 const Solution = (S) =>
  S.split('').reduce((acc, cur, i, arr) => {
    const pre = acc[acc.length - 1]
    const nex = arr[i + 1]
    if (cur !== '?') acc += cur
    else {
      acc += replaceWildcard(pre, nex)
    }
    return acc
  }, '')

 const test = (str) => str.split('').reduce((acc, cur, i, arr) => {
  if (acc === false) return acc
  const pre = arr[i - 1]
  const nex = arr[i + 1]
  if ([pre, nex].includes(cur)) acc = false
  return acc
 }, true)

 ////////////////////////////////////////////

 const t1 = 'ab?ac?'
 const t2 = 'rd?e?wg??'
 const t3 = '????????'
 table([
  { riddle: t1, result: Solution(t1), pass: test(Solution(t1)) },
  { riddle: t2, result: Solution(t2), pass: test(Solution(t2)) },
  { riddle: t3, result: Solution(t3), pass: test(Solution(t3)) }
 ])