HDU1398(母函数)

大意：有不通面值的硬币，对于给定的值有多少组成方法。

分析：构造母函数(1+x+x^2+x^3+...)(1+x^4+x^8+.....)...(1+x^209+x^508+....)。

代码：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;
int c1[305], c2[305];
int a[17] = { 1,4,9,16,25,36,49,64,81,100,121,144,169,196,225,256,289 };
int main()
{
	int n;
	while (scanf("%d", &n) != EOF)
	{
		for (int i = 0; i <= n; i++)
		{
			c1[i] = 1;
			c2[i] = 0;
		}
		for (int i = 2; i <= n; i++)
		{
			for (int j = 0; j <= n; j++)
				for (int k = 0; k + j <= n; k += i)
					c2[k + j] += c1[j];
			for (int j = 0; j <= n; j++)
			{
				c1[j] = c2[j];
				c2[j] = 0;
			}
		}
		printf("%d\n", c1[n]);
	}
	return 0;
}