Hdu2159 dual full backpack

Different from a general backpack, an item selection restriction is added. Therefore, you need to add one dimension.

DP [I] [J] [k] indicates the first I items. Select J items and put them in a backpack with K capacity to obtain the maximum value.

Here, like a one-dimensional backpack, you can use a rolling array to omit one-dimensional

DP [I] [J] indicates the maximum value that a backpack with the size of J can obtain.

DP [I, j] = max (DP [I, j], DP [I-1] [J-W [k] + V [k]);

 

 1 #include <cstdio> 2 #include <cstring> 3 #include <string> 4 #include <algorithm> 5 #include <iostream> 6 using namespace std; 7 #define INF 0x3fffffff 8 const int maxn = 105; 9 const int maxv = 105;10 int dp[maxv][maxn],w[maxn],v[maxn];11 int main()12 {13    //freopen("in.txt","r",stdin);14     int n,m,k,s;15     while(cin>>n>>m>>k>>s)16     {17         for(int i = 1;i<=k;++i)18             scanf("%d%d",v+i,w+i);19         memset(dp,0,sizeof(dp));20         int flag = 0,ans = -1;21         for(int j = 0;j<=m;++j)22         {23             for(int i = 1;i<=s;++i)24             {25                 for(int x = 1;x<=k;++x)26                     if(j>=w[x]){27                             dp[i][j] = max(dp[i][j],dp[i-1][j-w[x]]+v[x]);28                             if(dp[i][j]>=n){flag = 1;ans = j;break;}29                     }30                 if(flag)break;31             }32             if(flag)break;33         }34         if(flag)printf("%d\n",m-ans);35         else puts("-1");36     }37     return 0;38 }

 

Hdu2159 dual full backpack