bzoj3594: [Scoi2014]方伯伯的玉米田

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
int maxn,n,k,a[10010],ans,tmp;

struct BIT {
    int c[6060][550];
    
    inline int lowbit(int x) {
        return x&-x;
    }
    
    void update(int x,int y,int val) {
        for(int i=x;i<=maxn+k;i+=lowbit(i))
        for(int j=y;j<=k+1;j+=lowbit(j))
            c[i][j]=max(c[i][j],val);
    }
    
    int get(int x,int y) {
        int res=0;
        for(int i=x;i;i-=lowbit(i))
        for(int j=y;j;j-=lowbit(j))
            res=max(res,c[i][j]);
        return res;
    }
}bit;

int main() {
    scanf("%d%d",&n,&k);
    for(int i=1;i<=n;i++) {
        scanf("%d",&a[i]);
        maxn=max(maxn,a[i]);
    }
    for(int i=1;i<=n;i++)
    for(int j=k;~j;j--) {
        //printf("t%d %d\n",i,j);
        tmp=bit.get(a[i]+j,j+1)+1;
        ans=max(ans,tmp);
        bit.update(a[i]+j,j+1,tmp);
    }
    printf("%d\n",ans);
    return 0;
}