首页 > 代码库 > LeetCode: Letter Combinations of a Phone Number 解题报告
LeetCode: Letter Combinations of a Phone Number 解题报告
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"].
Note:
Although the above answer is in lexicographical order, your answer could be in any order you want.
SOLUTION 1:
经典递归模板。
注意这一行不要写错了，根据当前的数字来取得可能的字母组合：
//get the possiable selections.
String s = map[digits.charAt(index) - ‘0‘];
1 public class Solution { 2 String[] map = {"", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"}; 3 4 public List<String> letterCombinations(String digits) { 5 List<String> ret = new ArrayList<String>(); 6 if (digits == null) { 7 return ret; 8 } 9 10 dfs(digits, new StringBuilder(), ret, 0);11 return ret;12 }13 14 public void dfs(String digits, StringBuilder sb, List<String> ret, int index) {15 int len = digits.length();16 if (index == len) {17 ret.add(sb.toString());18 return;19 }20 21 // get the possiable selections.22 String s = map[digits.charAt(index) - ‘0‘];23 for (int i = 0; i < s.length(); i++) {24 sb.append(s.charAt(i));25 dfs(digits, sb, ret, index + 1);26 sb.deleteCharAt(sb.length() - 1);27 }28 }29 30 }
GITHUB:
https://github.com/yuzhangcmu/LeetCode_algorithm/blob/master/combination/LetterCombinations.java
LeetCode: Letter Combinations of a Phone Number 解题报告
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。