Question Definition
Given a digit string, 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.
Input:Digit string "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.
Java Solution
public List<String> letterCombinations(String digits) {
String[] nums = {"", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
List<String> result = new LinkedList<>();
for(char c : digits.toCharArray()){
List<String> temp = new LinkedList<>();
for(char s : nums[c - '0'].toCharArray()){
if(result.isEmpty())
temp.add("" + s);
else
for(String res : result)
temp.add(res + s);
}
result = temp;
}
return result;
}
Comments