I'm working on the game in C++. Basically, the game is going to be a simulation of the world with some animals, plants, and of course a player itself (Animals move in random directions). I wanna do it to practice OPP, algorithm library, and work a little with collections from STL. I want to mention that I'm rewriting this project, and there is only one concern that keeps bothers me - Checking collisions. The game is going to be two-dimensional (only x,y coordinates).
Because if I keep my organisms in vector it's going to take a linear time to find if there are other organisms on these coordinates. When there is more organisms, this search takes a lot of time (seriously, for 400 animals their turn could take 20-30 seconds). So my question is, which STL collection would fit my problem best. Thank you in advance for your help.
Animals may die, their strength may be modified, and they can also create offsprings.