自己看

#include <utility>
#include <string>
#include <iostream>
#include <vector>
#include <list>
#include <sstream>

std::string response(
  const std::vector<std::pair<std::vector<std::string>,std::string>>& cmds,
  const std::string& cmd){
    std::list<std::pair<std::vector<std::string>,std::string>> 
        temp_ls (cmds.begin(),cmds.end());
    std::istringstream iss(cmd);
    std::string temp ;
    int tk_c = -1;
    while(std::getline(iss,temp,' ')){
        tk_c++;
        for(int i=0;i<temp.size();++i){
            for(auto it = temp_ls.begin();it != temp_ls.end();){
                if(it->first.size() <= tk_c ||
                  it->first.at(tk_c).at(i) != temp.at(i)){
                    auto jt = it;
                    it++;
                    temp_ls.erase(jt);
                }else{
                    it++;
                }
            }
        }

    }
    if(temp_ls.size() > 1){
        for(auto it = temp_ls.begin();it != temp_ls.end();){
            if(it->first.size() > tk_c+1){ 
                auto jt = it;
                it++;
                temp_ls.erase(jt);
            }
            else{it++;}
        }
    }
    if(temp_ls.size() != 1){return "unknown command";}
    return temp_ls.back().second;
}

int main(){
    std::vector<std::pair<std::vector<std::string>,std::string>> cmds {
        {{"reset"}    ,"reset what"},
        {{"reset","board"},    "board fault"},
        {{"board","add"}    ,"where to add"},
        {{"board","delete"}    ,"no board at all"},
        {{"reboot","backplane"},    "impossible"},
        {{ "backplane","abort"},    "install first"},
    };
    std::string input_cmd;
    while(std::getline(std::cin,input_cmd)){
        std::cout << response(cmds,input_cmd) << std::endl;
    }
    return 0;

}