设有n 种不同的钱币各若干张，可用这n 种钱币产生许多不同的面值。试

设计一个算法，计算给定的某个面值，能有多少种不同的产生方法。例如有1 分3 张，2 分

3 张，5 分1 张，则能组成7 分面值的方法有：3 个1 分+2 个2 分，1 个1 分+3 个2 分，2

个1 分+1 个5 分，1 个2 分+1 个5 分共四种。-With n different number of sheets of each coin, can produce these n many different kinds of coin denomination. Try to design an algorithm to calculate a given nominal value, can have many different methods of production. For example there is a sub-3, 2 points 3, 5 1, the nominal value can be composed of seven points are: 3 points 2 points 1 point+2, a 1 minute+3 a 2 points, 2 1 minute+1 5 points, 2 points+1 a total of four points in five minutes.