Leetcode-Letter Combinations of a Phone Number-白红宇

Leetcode-Letter Combinations of a Phone Number

阅读量：5283 次

发布时间：2019-06-14

本文共 1669 字，大约阅读时间需要 5 分钟。

题目:

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.

采用dfs深度搜索.

1 #include 
     
       2 #include 
       3 #include 
       
         4 #include 
        
          5  6 class Solution{ 7 private: 8        map
         
          
            > dict; 9 vector
           
             res;10 public:11 void createDict()12 {13 dict.clear();14 dict['2'].push_back('a');15 dict['2'].push_back('b');16 dict['2'].push_back('c');17 dict['3'].push_back('d');18 dict['3'].push_back('e');19 dict['3'].push_back('f');20 dict['4'].push_back('g');21 dict['4'].push_back('h');22 dict['4'].push_back('i');23 dict['5'].push_back('j');24 dict['5'].push_back('k');25 dict['5'].push_back('l');26 dict['6'].push_back('m');27 dict['6'].push_back('n');28 dict['6'].push_back('o');29 dict['7'].push_back('p');30 dict['7'].push_back('q');31 dict['7'].push_back('r');32 dict['7'].push_back('s');33 dict['8'].push_back('t');34 dict['8'].push_back('u');35 dict['8'].push_back('v');36 dict['9'].push_back('w');37 dict['9'].push_back('x');38 dict['9'].push_back('y');39 dict['9'].push_back('z');40 }41 42 void dfs(int dep,int maxDep,string &s,string ans){43 if(dep==maxDep){44 res.push_back(ans);45 return;46 }47 48 for(int i=0;i
            
              letterCombinations(string digits){54 res.clear();55 createDict();56 dfs(0,digits.size(),digits,"");57 }58 59 };