POJ 1293 - Duty Free Shop 01背包记录所选物品

裸的01背包.dp[x]只要是bool型记录当前空间是否可用..

而为了找到用了哪些物品..dp[x]设置为int型..进行记录..

Program:

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<cmath>
#define oo 1000000007
#define ll long long
#define pi acos(-1.0)
#define MAXN 20005
using namespace std;
int M,L,N,w[MAXN],dp[MAXN],ans[MAXN];
bool used[MAXN];
int main()
{
     // freopen("input.txt","r",stdin);   freopen("output.txt","w",stdout);
      int i,j,x,num,sum;
      while (~scanf("%d%d",&M,&L))
      {
              if (!M && !L) break;
              scanf("%d",&N);
              memset(dp,-1,sizeof(dp));
              sum=0;
              dp[0]=0;
              for (i=1;i<=N;i++) scanf("%d",&w[i]);
              for (i=1;i<=N;i++)
              {
                     x=w[i];
                     sum+=x;
                     for (j=M-x;j>=0;j--)
                       if (dp[j]!=-1 && dp[j+x]==-1)
                         dp[j+x]=i;
              }
              for (;M>=0;M--)
              if (sum-M<=L && dp[M]!=-1)
              {
                     x=M;
                     num=0;
                     while (x)
                     {
                          ans[++num]=dp[x];
                          x=x-w[dp[x]];
                     }
                     printf("%d",num);
                     for (i=num;i>=1;i--) printf(" %d",ans[i]);
                     break;
              }
              if (M<0) printf("Impossible to distribute");
              printf("\n");
      }
      return 0;
}