i have a question. I have a lot of data in a 2d array and want to know the most efficient way to save it. It mainly has numbers of long long. Is vector of vectors a good idea where one vector holds the info of a row and the other vector the starting address of each row? If there be an better way please help!!
Since 80% of my matrix is full of 0s i think using a map nested in a vector would be a better idea. However I am having trouble with syntax coz I defined it like: std::vector< std::map<std::string,longlong> > data; but now how do I add an element or value???