cf 506 A. Mr. Kitayuta, the Treasure Hunter

不知道这个sb题怎么做错了。。

 /*#include <bits/stdc++.h>
 #define LL long long
 using namespace std;
 inline int ra()
 {
     int x=0,f=1; char ch=getchar();
     while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
     while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
     return x*f;
 }
 int n,s,tot[30005],f[30005],ans;
 bool can[30005][605];
 const int T=300;
 int main()
 {
     n=ra(); s=ra(); can[0][T]=1;
     for (int i=1; i<=n; i++) tot[ra()]++;
     f[0]=tot[0];
     for (int i=0; i<=30000; i++)
     {
         for (int j=-300; j<=300; j++)
         {
             if (s+j<=0) continue;
             if (can[i][j+T] && s+i+j<=30000)
             {
                 f[s+i+j]=max(f[i+j+s],f[i]+tot[s+i+j]);
                 can[i+j+s][j+T]=1;
                 can[i+j+s][j+1+T]=1;
                 can[i+j+s][j-1+T]=1;
             }
         }
         ans=max(ans,f[i]);
     }
     cout<<ans;
     return 0;
 }*/
 #include <bits/stdc++.h>
 #define LL long long
 using namespace std;
 inline int ra()
 {
     int x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 const int T=;
 int n,s,ans;
 int tot[],f[][];
 int main()
 {
     memset(f,-,sizeof(f));
     n=ra(); s=ra();
     for (int i=; i<=n; i++) tot[ra()]++;
     f[s][T/]=;
     for (int i=s; i<=; i++)
         for (int j=; j<=T; j++)
         {
             int t=j-T/+s;
             if (i-t>= && t>)
             {
                 if (f[i-t][j-]!=-) f[i][j]=max(f[i][j],f[i-t][j-]);
                 if (f[i-t][j]!=-) f[i][j]=max(f[i][j],f[i-t][j]);
                 if (f[i-t][j+]!=-) f[i][j]=max(f[i][j],f[i-t][j+]);
                 if (f[i][j]!=-) f[i][j]+=tot[i];
                 ans=max(f[i][j],ans);
             }
         }
         cout<<ans;
         return ;
 }