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17 Letter Combinations of a Phone Number Leetcode Problem Javascript Solution

Letter Combinations of a Phone Number
Medium
Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent.
A mapping of digit to letters (just like on the telephone buttons) is given below. Note that 1 does not map to any letters.
Example:
Input: "23"
Output: ["ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf"].
Note:
Although the above answer is in lexicographical order, your answer could be in any order you want.
RUN THE CODE HERE: https://repl.it/@VinitKhandelwal/telephone-text-javascript-leetcode

For people looking for solution in Javascript, here is a recursive solution. for other languages, please convert the code

const group = [];
result = [];
let numstr = "";
var letterCombinations = function(num) {
  numstr = num.toString();
  const letters = [,,['a','b','c'],['d','e','f'],['g','h','i'],['j','k','l'],['m','n','o'],['p','q','r','s'],['t','u','v'],['w','x','y','z']];
  for (let i=0; i<numstr.length; i++) {
    group.push(letters[parseInt(numstr[i])]);
  }
  wordMaker(num, 0, "");
  return result;
}

const wordMaker = (num, n, w) => {
  for (let i=0; i<group[n].length; i++) {
    if (n === group.length-1) {
      result.push(w + group[n][i])
    }
    else {
      wordMaker(num, n+1, w + group[n][i]);
    }
  }
}

Test Input

console.log(letterCombinations(23));

Output

[ 'ad', 'ae', 'af', 'bd', 'be', 'bf', 'cd', 'ce', 'cf' ]


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