pku 1837 Balance (01背包)

pku 1837 Balance (01背包)

01 背包问题.

f[i][j] 表示将前i个物品放入力矩为j的可行方案

f[i][j] = sum{ f[i-1][j-w[i][k] }

#include  < iostream >

using   namespace  std;

const   int  mid  =   6000 ;

int  w[ 25 ],v[ 25 ];
int  f[ 25 ][mid + mid];

int  C,G;

int  main() {
    int i,j,k;

    cin>>C>>G;

    for(i=1; i<=C; ++i) cin>>v[i];
    for(i=1; i<=G; ++i) cin>>w[i];

    for(i=1; i<=C; ++i)
        f[1][mid+v[i]*w[1]] = 1;

    for(i=2; i<=G; ++i)
        for(j=1; j<=C; ++j)
            for(k=0; k<=2*mid; ++k)
                if(f[i-1][k]>0)
                    f[i][k+w[i]*v[j]] += f[i-1][k];

    cout<<f[G][mid]<<endl;

    return 0;
}