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.
Brute force method can be accepted by leetcode online judge.
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public
class
Solution { public
ArrayList<String> letterCombinations(String digits) { String[] keyboard = new
String[]{"","","abc","def","ghi","jkl","mno", "pqrs","tuv","wxyz"}; ArrayList<String> result = new
ArrayList<String>(); result.add(""); for(int
i = 0; i < digits.length(); ++i){ int
k = digits.charAt(i) - 48; if(k != 0
&& k != 1){ ArrayList<String> temp = new
ArrayList<String>(); while(!result.isEmpty()){ String s = result.remove(0); for(int
j = 0; j < keyboard[k].length(); ++j){ StringBuffer stb = new
StringBuffer(s); stb.append(keyboard[k].charAt(j)); temp.add(stb.toString()); } } result = temp; } } return
result; }} |
leetcode--Letter Combinations of a Phone Number
原文：http://www.cnblogs.com/averillzheng/p/3536934.html