acm题，纪念邮票邮局最近推出了一套纪念邮票，这套邮票共有N张，邮票面值各不相同，按编号顺序为1分，2分，……，N分。小明是个集邮爱好者，他很喜欢这套邮票，可惜现在他身上只有M分，并不够把全套都买下。他希望尽量买，最好刚好花光所有的钱。作为一个集邮爱好者，小明也不想买的邮票编号断断续续，所以小明打算买面值a分至b分的b-a+1张连续的邮票，且总价值刚好为M分。 我们用不同的算法求出所有符合要求的方案，以[a，b]的形式输出。-acm questions, post office recently launched a commemorative set of commemorative stamps, stamps are a total of N sheets, stamps face value varies in numerical order of 1 minute, 2 minutes, ......, N points. Xiao Ming is a stamp collector, he was very fond of the stamps, but now his body is only M points, and not enough to have bought a full set. He hoped that try to buy the best just spend all the money. As a philatelists, Xiao Ming not want to buy stamps numbers off, so Xiao Ming intend to buy a par value b min b-a+1 continuous sheets of stamps, and the total value of M points exactly. We use different algorithms to obtain all eligible programs to [a, b] in the form of output.