力扣-回溯-17电话号码的字母组合

思路

和之前的回溯不同的是，要遍历完所有的数字，并且在单层递归逻辑里需要遍历一整个字符串

代码 class Solution { public: vector<string> letters = {"", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"}; vector<string> result; string path; void backTracking(string dights, int curIndex){ if(curIndex == dights.size()){ result.push_back(path); return; } string letter = letters[(char)dights[curIndex] - '0']; for(int i = 0; i < letter.size(); i++){ path.push_back(letter[i]); backTracking(dights, curIndex+1); path.pop_back(); } return; } vector<string> letterCombinations(string digits) { if(digits == "") return result; backTracking(digits, 0); return result; } };