[Leetcode] Letter Combinations of a Phone Number

数字转字母组合

最新推荐文章于 2020-08-10 10:20:18 发布

转载最新推荐文章于 2020-08-10 10:20:18 发布 · 65 阅读

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原文链接：http://www.cnblogs.com/Phoebe815/p/4094694.html

通过给定的数字字符串，实现将其转换为对应的字母组合，并详细解释了实现过程和使用示例。

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.

Solution:

 1 public class Solution {
 2     public List<String> letterCombinations(String digits) {
 3         String[] maps={""," ","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
 4         List<String> result = new ArrayList<String>();
 5         dfs(result, maps, digits,0,"");
 6         return result;
 7     }
 8 
 9     private void dfs(List<String> result, String[] maps, String digits, int level, String temp) {
10         // TODO Auto-generated method stub
11         if(level>digits.length())
12             return;
13         if(digits.length()==level){
14             result.add(temp);
15             return;
16         }
17         int curDig=digits.charAt(level)-48;
18         for(int i=0;i<maps[curDig].length();++i){    //此时从0开始到maps[curDig]结束，为temp里可以加的字母的取值范围
19             temp+=maps[curDig].charAt(i);
20             dfs(result, maps, digits, level+1, temp);
21             temp=temp.substring(0, temp.length()-1);
22         }    
23     }
24 }

转载于:https://www.cnblogs.com/Phoebe815/p/4094694.html