回溯法,然后用set去重 class Solution { public: string s; vector<string>result; void backtracking(string str,int len,int index){ if(index==len){ result.push_back(str); return; } for(int i=index;i<len;++i ){ swap(str[i],str[index]); backtracking(str,len,index+1); swap(str[i],str[index]); } } vector<...