POJ 1015 Jury Compromise

/**/ /**************************************
Problem: POJ 1015 Jury Compromise
Time: 32MS
Memory: 440K
Accepted Time: 2009-04-12 14:21:50
Tips:《程序设计导引及在线实践》10.6，有点难以理解 
**************************************/
#include  < stdio.h >
#include  < stdlib.h >
#include  < string .h >
int  f[ 30 ][ 1000 ];
int  Path[ 30 ][ 1000 ];
int  P[ 300 ];
int  D[ 300 ];
int  Answer[ 30 ];
int  CompareInt( const   void   * e1, const   void   * e2)
{
    return *((int*)e1)-*((int*)e2);
}
int  main()
{
    int i,j,k;
    int t1,t2;
    int n,m;
    int nMinP_D;
    int nCaseNo=1;
    while(1)
    {
        scanf("%d%d",&n,&m);
        if(n==0&&m==0)break;
        for(i=1;i<=n;i++)scanf("%d%d",&P[i],&D[i]);
        memset(f,-1,sizeof(f));
        memset(Path,-1,sizeof(Path));
        nMinP_D=m*21;
        f[0][nMinP_D]=0;
        for(j=0;j<m;j++)
        {
            for(k=0;k<=nMinP_D*2;k++)
            {
                if(f[j][k]>=0)
                {
                    for(i=1;i<=n;i++)
                    if(f[j][k]+P[i]+D[i]>f[j+1][k+P[i]-D[i]])
                    {
                        t1=j;t2=k;
                        while(t1>0&&Path[t1][t2]!=i)
                        {
                            t2-=P[Path[t1][t2]]-D[Path[t1][t2]];
                            t1--;
                        }
                        if(t1==0)
                        {
                            f[j+1][k+P[i]-D[i]]=f[j][k]+P[i]+D[i];
                            Path[j+1][k+P[i]-D[i]]=i;
                        }
                    }
                }
            }
        }
        i=nMinP_D;j=0;
        while(f[m][i+j]<0&&f[m][i-j]<0)j++;
        if(f[m][i+j]>f[m][i-j])k=i+j;
        else k=i-j;
        printf("Jury #%d\n",nCaseNo++);
        printf("Best jury has value %d for prosecution and value %d for defence:\n",
        (k-nMinP_D+f[m][k])/2,(f[m][k]-k+nMinP_D)/2);
        for(i=1;i<=m;i++)
        {
            Answer[i]=Path[m-i+1][k];
            k-=P[Answer[i]]-D[Answer[i]];
        }
        qsort(Answer+1,m,sizeof(int),CompareInt);
        for(i=1;i<=m;i++)printf(" %d",Answer[i]);
        printf("\n\n");
    }
    return 0;
}