NOIP 考前DP 复习

POJ 2533 最长不降子序列

 #include <cstdio>
 const int Maxn=;
 int a[Maxn],Pos[Maxn],F[Maxn],n,Ans;
 inline int Max(int x,int y) {return x>y?x:y;}
 inline int Find(int x)
 {
     int l=,r=Ans,Res;
     while (l<=r)
     {
         int mid=(l+r)>>;
         if (a[Pos[mid]]<x) Res=mid,l=mid+;  else r=mid-;
     }
     return Res;
 }
 int main()
 {
     scanf("%d",&n);
     for (int i=;i<=n;i++) scanf("%d",&a[i]);
     F[]=; Pos[]=; Ans=;
     for (int i=;i<=n;i++)
     {
         int t=Find(a[i]);
         Pos[t+]=i;
         F[i]=t+;
         Ans=Max(Ans,F[i]);
     }
     printf("%d\n",Ans);
     return ;
 }

POJ 2533

BZOJ 3886

状压DP+贪心

 #include <cstdio>
 #include <cstring>
 const int Maxn=;
 const int Maxm=;
 const int Inf=0x3f3f3f3f;
 inline int Min(int x,int y) {return x>y?y:x;}
 inline int Max(int x,int y) {return x>y?x:y;}
 int n,m,f[<<Maxn],Ans=Inf;
 int Len[Maxn],P[Maxn],C[Maxn][Maxm];
 int find(int x,int id)
 {
     int l=,r=P[id];
     while (l<r)
     {
         int mid=(l+r+)>>;
         if (C[id][mid]<=x) l=mid;
         else r=mid-;
     }
     return l;
 }
 int main()
 {
     // freopen("c.in","r",stdin);
     scanf("%d%d",&n,&m);
     for (int i=;i<=n;i++)
     {
         scanf("%d%d",&Len[i],&P[i]);
         for (int j=;j<=P[i];j++) scanf("%d",&C[i][j]);
     }
     memset(f,-,sizeof(f)),f[]=;
     for (int i=;i<(<<n);i++)
     {
         if (f[i]==-) continue;
         if (f[i]>=m)
         {
             int j,k;
             for (j=,k=i;k;k-=(k&(-k))) j++;
             Ans=Min(Ans,j);
             continue;
         }
         for (int j=;j<=n;j++)
         {
             if (i&(<<(j-))) continue;
             int k=find(f[i],j);
             if (k==) continue;
             f[i|(<<(j-))]=Max(f[i|(<<(j-))],C[j][k]+Len[j]);
         }
     }
     printf("%d\n",Ans==Inf?-:Ans);
     return ;
 }

BZOJ 3886