hdu 2639求背包第K大值

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本文介绍了一种解决背包问题的变种——求第K大价值的问题。通过使用额外的一维数组记录不同级别的最大价值，并采用两个队列合并的方式来更新状态，确保了结果的准确性。文章提供了一个具体的实现示例。

求第K大值得模板题，只需要多加一维来记录第X大。

然后状态转移由以前的一个方程，变成两个队列的合并，注意合并的时候去重就行

Problem Description

The title of this problem is familiar,isn't it?yeah,if you had took part in the "Rookie Cup" competition,you must have seem this title.If you haven't seen it before,it doesn't matter,I will give you a link:

Here is the link: http://acm.hdu.edu.cn/showproblem.php?pid=2602

Today we are not desiring the maximum value of bones,but the K-th maximum value of the bones.NOTICE that,we considerate two ways that get the same value of bones are the same.That means,it will be a strictly decreasing sequence from the 1st maximum , 2nd maximum .. to the K-th maximum.

If the total number of different values is less than K,just ouput 0.

Input

The first line contain a integer T , the number of cases.
Followed by T cases , each case three lines , the first line contain two integer N , V, K(N <= 100 , V <= 1000 , K <= 30)representing the number of bones and the volume of his bag and the K we need. And the second line contain N integers representing the value of each bone. The third line contain N integers representing the volume of each bone.

Output

One integer per line representing the K-th maximum of the total value (this number will be less than 2 ³¹).

Sample Input

Sample Output

  
   12
2
0
  
  
   #include<iostream>
#include<algorithm>
using namespace std;
const int maxn = 1005;

int N, V, K;
int csti[110],vi[110];
int f[maxn][31];

inline void zoPack(int cost, int weight){
	for(int i=V;i>=cost;--i)
	{	
		int foobar[2*K],ctr = 0;;
		for(int j = 1;j<=K;++j)
		{
			foobar[ctr++] = f[i][j];
			foobar[ctr++] = f[i-cost][j] + weight;
		}
		sort(foobar,foobar + ctr);/*最好这样合并队列*/
		f[i][1] = foobar[--ctr];
		for(int j = 2; j<=K ; ++j)
		{
			while(f[i][j-1] == foobar[--ctr] && ctr >=0); /*注意--的使用..*/ 
			if( ctr < 0) break;
			f[i][j] = foobar[ctr];
		}
	}
}

int main(){
	int t;
	scanf("%d",&t);
	while(t--){
		scanf("%d%d%d",&N,&V,&K);
		memset(f,0,sizeof(f));

		for(int i=0;i<N;++i)
		scanf("%d",vi+i);
		for(int i=0;i<N;++i)
		scanf("%d",csti+i);
		
		for(int i=0;i<N;++i){
			zoPack(csti[i],vi[i]);
		}
		printf("%d\n",f[V][K]);
	}
	return 0;
}