C++，如何复制矢量<pair<int,int> &gt;pr 到一个向量<vector<int> &gt;vec </vector<int></pair<int,int>

Question

We have given a vector<pair<int,int>> pr = {{1,2},{2,3}} and we have to convert it into vector<vector>vec = {{1,2},{2,3}};

Answer 1

 for(auto it:pr){ 
    vec.push_back({it.first,it.second}); // insert it.first = 1, it.second = 2
}
//Print vector<vector<int>>vec
for(int i=0;i<vec.size();i++){
    for(int j=0;j<vec[0].size();j++){
        cout<<vec[i][j]<<" ";
    }`[enter code here][1]`
    cout<<endl;
}