【HDU】1171 - Big Event in HDU（母函数）

点击打开题目

Big Event in HDU

Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 35142 Accepted Submission(s): 12186

Problem Description

Nowadays, we all know that Computer College is the biggest department in HDU. But, maybe you don't know that Computer College had ever been split into Computer College and Software College in 2002. The splitting is absolutely a big event in HDU! At the same time, it is a trouble thing too. All facilities must go halves. First, all facilities are assessed, and two facilities are thought to be same if they have the same value. It is assumed that there is N (0<N<1000) kinds of facilities (different value, different kinds).

Input

Input contains multiple test cases. Each test case starts with a number N (0 < N <= 50 -- the total number of different facilities). The next N lines contain an integer V (0<V<=50 --value of facility) and an integer M (0<M<=100 --corresponding number of the facilities) each. You can assume that all V are different. A test case starting with a negative integer terminates input and this test case is not to be processed.

Output

For each case, print one line containing two integers A and B which denote the value of Computer College and Software College will get respectively. A and B should be as equal as possible. At the same time, you should guarantee that A is not less than B.

Sample Input

   2
10 1
20 1
3
10 1 
20 2
30 1
-1

Sample Output

   20 10
40 40

Author

lcy

昨天用01背包写的，看时间这么长，用母函数试了一下，还真的可以过。

01背包的方法：点击打开链接

代码如下：

#include <cstdio>
#include <cstring>
struct node
{
	int v,ant;
}data[55];
int main()
{
	int n;
	int sum;
	int c[250000+11];
	int t[250000+11];
	while (~scanf ("%d",&n) && n >= 0)
	{
		sum = 0;
		memset (c,0,sizeof (c));
		memset (t,0,sizeof (t));
		for (int i = 1 ; i <= n ; i++)
		{
			scanf ("%d %d",&data[i].v,&data[i].ant);
			sum += data[i].v * data[i].ant;
		}
		for (int i = 0 ; i <= data[1].v * data[1].ant && i <= sum ; i += data[1].v)
			c[i] = 1;
		for (int i = 2 ; i <= n ; i++)
		{
			for (int j = 0 ; j <= sum ; j++)
				for (int k = 0 ; k+j <= sum && k <= data[i].ant*data[i].v ; k += data[i].v)
					t[k+j] += c[j];
			for (int j = 0 ; j <= sum ; j++)
			{
				c[j] = t[j];
				t[j] = 0;
			}
		}
		for (int i = (sum >> 1) ; i >= 0 ; i--)
		{
			if (c[i])
			{
				printf ("%d %d\n",sum - i,i);
				break;
			}
		}
	}
	return 0;
}