实验名称：用动态规划法求解最长路径问题

设计动态规划算法求解最长路径问题（见下面附录部分），要求程序能根据给定的图作为输入，输出最长路径的长度及一条最长的路径。-Experiment name: the dynamic programming method for solving the longest path problem design dynamic programming algorithm for the longest path problem (see the appendix section below), the program according to a given graph as input, output length of the longest path and a longest paths.