The Hierarchical Mixed Rural Postman Problem
研究混合图中带层级顺序的弧和边服务问题，提出数学规划与禁忌搜索两种算法，实验表明其优于分支切割算法的一小时解。
In this paper, we study a generalization of the Hierarchical Chinese Postman Problem on a mixed graph where only a subset of arcs and edges require a service to be accomplished following a hierarchical order. The problem, called the Hierarchical Mixed Rural Postman Problem, also generalizes the Rural Postman Problem and thus is NP-hard. We propose a new mathematical formulation, and introduce two effective solution algorithms. The first procedure is a matheuristic that is based on the exact solution of a variant of the Mixed Rural Postman Problem for each hierarchy. The second approach is a tabu search algorithm based on different improvement and diversification strategies. Computational results on an extended set of instances show how the proposed solution methods are quite effective and efficient when compared to the solutions of a branch-and-cut algorithm stopped after one hour of computation.