2018实习生在线编程测验题，C++研发岗，求大神答疑解惑

#include <vector>

#include <iostream>

#include <sstream>

#include <string>

#include <vector>

#include <limits.h>

using namespace std;

/** 请完成下面这个函数，实现题目要求的功能 **/

 /** 当然，你也可以不按照这个模板来作答，完全按照自己的想法来 ^-^  **/

int minCost(vector<vector<int>>& costs)

{

}

int main()

{

       int N,K;

       int cost;

       vector<vector<int> > costs;

       string s;

       istringstream is;

       getline(cin, s);

       is.str(s);

       is>>N>>K;

       for(int i =0 ; i < N; i++)

       {

              vector<int> t;

              getline(cin, s);

              is.clear();

              is.str(s);

              for(int j = 0; j < K; j++) {

                     is >> cost;

                     t.push_back(cost);

              }

              costs.push_back(t);

       }

       cout<<minCost(costs)<<endl;

       return 0;

}