In computer science, a space-time or time-memory tradeoff is a way of solving a problem or calculation in less time by using more storage space (or memory), or by solving a problem in very little space by spending a long time. Most computers have a large amount of space, but not infinite space. Also, most people are willing to wait a little while for a big calculation, but not forever. So if your problem is taking a long time but not much memory, a space-time tradeoff would let you use more memory and solve the problem more quickly. Or, if it could be solved very quickly but requires more memory than you have, you can try to spend more time solving the problem in the limited memory.