Leetcode#17 Letter Combinations of a Phone Number

原题地址

 

简单DFS题目

 

代码：

 1 vector<string> res;

 2     

 3 void dfs(string &digits, vector<string> &i2s, string ans, int pos) {

 4   if (pos == digits.length()) {

 5     res.push_back(ans);

 6     return;

 7   }

 8         

 9   for (auto c : i2s[digits[pos] - '0'])

10     dfs(digits, i2s, ans + c, pos + 1);

11 }

12 

13 vector<string> letterCombinations(string digits) {

14   vector<string> i2s {"", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};

15   dfs(digits, i2s, "", 0);

16   return res;

17 }