首页 > 代码库 > Letter Combinations of a Phone Number
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.
主要是建立数字字母映射表，然后依次对每个数字所对应的字母进行深搜，代码如下：
1 class Solution { 2 public: 3 vector<string> letterCombinations(string digits) { 4 vector<string> vstr(9); //建立数字映射字母表 5 char ch = ‘a‘; 6 for(int i=1; i<9; ++i) { 7 if( i == 6 || i == 8) { 8 int cnt = 4; 9 while( cnt-- ) vstr[i].push_back(ch++);10 }11 else {12 int cnt = 3;13 while( cnt-- ) vstr[i].push_back(ch++);14 }15 }16 ans.clear();17 string str;18 dfs(digits, vstr, 0, str); //深搜19 return ans;20 }21 22 void dfs(string& digits, vector<string>& vstr, int k, string& str) {23 if( k == digits.length() ) { //如果搜到了末尾，str就是答案之一24 ans.push_back(str);25 return;26 }27 int index = digits[k]-‘0‘-1; //取对应数字在映射表中的位置28 for(int i=0; i<vstr[index].size(); ++i) { //对每个数字所代表字母的进行深搜29 str.push_back(vstr[index][i]);30 dfs(digits, vstr, k+1, str);31 str.pop_back();32 }33 }34 35 private:36 vector<string> ans;37 };
Letter Combinations of a Phone Number
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。