declaring 2d vector code example
Example 1: 2d vector c++ declaration
vector< vector<int>> a(rows, vector<int> (cols));
Example 2: initializing 2d vector
vector<vector<int> > vec( n , vector<int> (m, 0));
vector< vector<int>> a(rows, vector<int> (cols));
vector<vector<int> > vec( n , vector<int> (m, 0));