BZOJ 1606: [Usaco2008 Dec]Hay For Sale 购买干草( dp )

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#include<cstdio>

#include<algorithm>

#include<iostream>

#include<cstring>

 

#define rep( i , n ) for( int i = 0 ; i < n ; ++i )

#define clr( x , c ) memset( x , c , sizeof( x ) )

 

using namespace std;

 

const int maxn = 50000 + 5;

 

bool dp[ maxn ];

 

int main() {

freopen( "test.in" , "r" , stdin );

clr( dp , 0 );

int n , V;

cin >> V >> n;

while( n-- ) {

int t;

scanf( "%d" , &t );

for( int i = 0 ; i + t <= V ; i++ ) 

   if( dp[ i ] ) dp[ i + t ] = true;

   

dp[ t ] = true;

   

}

for( int i = V ; i >= 0 ; i-- ) if( dp[ i ] ) {

cout << i << "\n";

break;

}

return 0;

}

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1606: [Usaco2008 Dec]Hay For Sale 购买干草

Time Limit: 5 Sec  Memory Limit: 64 MB
Submit: 743  Solved: 560
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Description

    约翰遭受了重大的损失：蟑螂吃掉了他所有的干草，留下一群饥饿的牛．他乘着容量为C(1≤C≤50000)个单位的马车，去顿因家买一些干草．  顿因有H(1≤H≤5000)包干草，每一包都有它的体积Vi(l≤Vi≤C).约翰只能整包购买，

他最多可以运回多少体积的干草呢？

Input

    第1行输入C和H，之后H行一行输入一个Vi．

Output

 

    最多的可买干草体积．

Sample Input

7 3 //总体积为7,用3个物品来背包
2
6
5

The wagon holds 7 volumetric units; three bales are offered for sale with
volumes of 2, 6, and 5 units, respectively.

Sample Output

7 //最大可以背出来的体积

HINT

Buying the two smaller bales fills the wagon.

Source

Silver