Improving Han and Lee´s path consistency algorithm

C.C. Han and C.H. Lee (1988) presented a path consistency algorithm. A new algorithm is described for path consistency, and it is shown that the algorithm requires less time and space than Han and Lee´s. The key idea of the algorithms is the arranging of the edges which are checked in the first part of Han and Lee´s algorithm and the interlacing of the second part of the algorithm in the first part by using the symmetry of the triangle