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hdu 1171 Big Event in HDU 多重背包

2024-07-05 09:23:30   235人阅读

Big Event in HDU


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
 

代码：

/**
*   本题题意：
*           给出每种石头的重量和个数，求尽量将这些石头分成两堆时，两堆石块的重量
*           这里消耗和价值都是石块的重量
*   解题思路：V=sum/2
*/
#include <string.h>
#include <stdio.h>
#define maxn 500005
int max(int a, int b){
	if (a > b)return a;
	return b;
}
int dp[maxn];
int weight[maxn];
int number[maxn];
int V;
//01
void zeroonepack(int c)
{
	for (int v = V; v >= c; v--)
		dp[v] = max(dp[v], dp[v - c] + c);
}
//完全
void completepack(int c)
{
	for (int v = c; v <= V; v++)
		dp[v] = max(dp[v], dp[v - c] + c);
}
//多重
void mupack(int c, int p)
{
	if (c*p >= V)
		completepack(c);
	else
	{
		int k = 1;
		while (k < p)
		{
			zeroonepack(k*c);
			p = p - k;
			k = k * 2;
		}
		zeroonepack(p*c);
	}
}
int main()
{
	int n;
	while (scanf("%d", &n), n >= 0)
	{
		int sum = 0;
		for (int i = 1; i <= n; i++)
		{
			scanf("%d%d", &weight[i], &number[i]);
			sum += weight[i] * number[i];
		}
		V = sum / 2;
		memset(dp, 0, sizeof(dp));
		for (int i = 1; i <= n; i++)
			mupack(weight[i], number[i]);
		int x = dp[V];
		int y = sum - x;
		if (x > y)
			printf("%d %d\n", x, y);
		else
			printf("%d %d\n", y, x);
	}
	return 0;
}


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