Backtracking

Backtracking is a powerful algorithmic technique that aims to solve a problem incrementally, by trying out an various sequences of decisions. If at any point it realizes that its current path will not lead to a solution, it reverses or "backtracks" the most recent decision and tries the next available route. Backtracking is often applied in problems where the solution requires the sequence of decisions to meet certain constraints, like the 8-queens puzzle or the traveling salesperson problem. In essence, it involves exhaustive search and thus, can be computationally expensive. However, with the right sorts of constraints, it can sometimes find solutions to problems with large and complex spaces very efficiently.