Leetcode之letter Combinations Of A Phone Number

26 June 2014

Letter Combinations of a Phone Number

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"].

解法：字符组合问题，一般用递归都能很快解决。

代码如下：

//{java}
public class Solution {
    public List<String> letterCombinations(String digits) {
        String []table = new String []{""," ","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
         List<String> ls= new ArrayList<String>();
        if(digits.length()==0)
        {
            ls.add("");
            return ls;
        }
        char c = digits.charAt(0);
       
        for(int i=0;i<table[c-48].length();i++)
        {
            char t = table[c-48].charAt(i);
            for(String temp:letterCombinations(digits.substring(1,digits.length())))
            {
                ls.add(t+temp);
            }
        }
        return ls;
    }
}

LeetCode 47

LeetCode，面试，字符，组合，递归 1

Leetcode之letter Combinations Of A Phone Number 字符组合

Letter Combinations of a Phone Number