iven a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order.

A mapping of digit to letters (just like on the telephone buttons) is given below. Note that 1 does not map to any letters.

Character c = digits.charAt(index); String letters = letterMap[c - '0']; for(int i = 0 ; i < letters.length() ; i ++){ findCombination(digits, index+1, s + letters.charAt(i)); } return; } }