Letter Combinations of a Phone Number

￡神魔★判官ぃ 2022-01-07 23:55 308阅读 0赞

题目描述：

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.

200px-Telephone-keypad2.svg.png

  1. Input:Digit string "23"
  2. 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.

　　

　　这道题不算难，想想就出来了。

solution：

  1. vector<string> letterCombinations(string digits) {
  2.     int n = digits.size();
  3.     vector<string> res;
  4.     if(n == 0)
  5.         return res;
  6.     res.push_back("");
  7.     string numap[] = {
  8.     "#","#","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
  9.     for (int i = 0;i < n;++i)
  10.     {
  11.         vector<string> tmp;
  12.         for(int j = 0;j < res.size();++j)
  13.             for(int k = 0;k < numap[digits[i]-'0'].size();++k)
  14.                 tmp.push_back(res[j] + numap[digits[i]-'0'][k]);
  15.         res = tmp;
  16.     }
  17.     return res;
  18. }

　　此题还有其他解法，《编程之美》中也有相似题目，暂时先这样了。

转载于:https://www.cnblogs.com/gattaca/p/4315884.html

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