The traveling-salesman problem (abstract)
Susan N. Twohig, Samuel O. Aletan · 1990
The traveling-salesman problem is one of the classical NP-Complete problems. No current algorithms are available which can solve these problems in polynomial time, that is, the number of steps grows as a polynomial according to the size of the input. The traveling-salesman problem involves a salesman who must make a tour of a number of cities using the shortest path available. For each number of cities n, the number of paths which must be explored is n!, causing this problem to grow exponentially rather than as a polynomial.