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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.
class Solution { public: void createMap(map<char,string> &dMap) { dMap[‘0‘]=""; dMap[‘1‘]=""; dMap[‘2‘]="abc"; dMap[‘3‘]="def"; dMap[‘4‘]="ghi"; dMap[‘5‘]="jkl"; dMap[‘6‘]="mno"; dMap[‘7‘]="pqrs"; dMap[‘8‘]="tuv"; dMap[‘9‘]="wxyz"; return; } void dfsDigits(int curDeep, vector<string> &res, string currStr, const string digits, map<char,string> dMap) { if (curDeep==digits.size()) { res.push_back(currStr); return; } for (int i=0; i<dMap[digits[curDeep]].size();i++) { dfsDigits(curDeep+1, res, currStr+dMap[digits[curDeep]][i], digits, dMap); } } vector<string> letterCombinations(string digits) { vector<string> res; const int len=digits.size(); map<char,string> dMap; createMap(dMap); dfsDigits(0, res, "", digits, dMap); return res; } };
leetcode[17]Letter Combinations of a Phone Number
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原文地址：http://www.cnblogs.com/Vae98Scilence/p/4283677.html
