$O(kn^2)$ 思路的暴力dp挂了

请问是假了还是出现了傻逼错误

#include<bits/stdc++.h>
using namespace std;
inline int read()
{
    int x=0,f=1;
    char ch=getchar();
    while(!isdigit(ch))
    {
        if(ch=='-')
            f=-1;
        ch=getchar();
    }
    while(isdigit(ch))
    {
        x=(x<<1)+(x<<3)+ch-'0';
        ch=getchar();
    }
    return x*f;
}
const int MAXN=505,MAXK=105,MAX=605;
int n,K;
pair<int,int>d[MAX];
int f[MAXN][MAXK];
int ans;
int main()
{
    n=read(),K=read();
    for(int i=1;i<=n;i++)
        d[i].first=read(),d[i].second=read(),f[i][0]=1;
    sort(d+1,d+n+1);
    for(int i=1;i<=n;i++)
        for(int j=1;j<=i-1;j++)
            if(d[i].first-d[j].first==1&&d[i].second==d[j].second)
                for(int k=0;k<=K;k++)
                    f[i][k]=max(f[i][k],f[j][k]+1);
            else if(d[i].first==d[j].first&&d[i].second-d[j].second==1)
                for(int k=0;k<=K;k++)
                    f[i][k]=max(f[i][k],f[j][k]+1);
            else if(d[i].first-d[j].first==2&&d[i].second==d[j].second)
                for(int k=1;k<=K;k++)
                    f[i][k]=max(f[i][k],f[j][k-1]+1);
            else if(d[i].first==d[j].first&&d[i].second-d[j].second==2)
                for(int k=1;k<=K;k++)
                    f[i][k]=max(f[i][k],f[j][k-1]+1);
    for(int i=1;i<=n;i++)
        for(int j=0;j<=K;j++)
            ans=max(ans,f[i][j]);
    printf("%d\n",ans);
    return 0;
}