神器段错误 到后面停止工作 查不出错

#include<iostream>
#include<math.h>
#include<algorithm>
using namespace std;
#define maxn 100005
int a[maxn],b[maxn],maxl[maxn][3];
void read(int &x)
{
    int f=1;x=0;char s=getchar();
    while(s<'0'||s>'9'){if(s=='-')f=-1;s=getchar();}
    while(s>='0'&&s<='9'){x=x*10+s-'0';s=getchar();}
    x*=f;
}

int main(){
    int n;
    read(n);
    for(int i=1;i<=n;i++){
        read(a[i]);
    }
    for(int i=1;i<=n;i++){
        read(b[i]);
    }

/*  for(int i=0;i<=n;i++)
        for(int j=0;i<=2;j++){
        cout<<maxl[i][j]<<","
        }*/
    int count = 1;
    int k = 1;

    do{
        count++;

        if(k==1){
            for(int i=1;i<=n;i++){
                if(a[count]==b[i])
                    maxl[i][k]=maxl[i-1][k-1]+1;

                if(a[count]!=b[i])
                    maxl[i][k]=max(maxl[i-1][k],maxl[i][k-1]);
            }
        }

        if(k==0){
            for(int i=1;i<=n;i++){
                if(a[count]==b[i])
                    maxl[i][k]=maxl[i-1][k+1]+1;

                if(a[count]!=b[i])
                    maxl[i][k]=max(maxl[i-1][k],maxl[i][k+1]);
            }           
        }

        if(k==1)
            k=0;
    }while(count <= n);

    int cmp=0;
    for(int i=0;i<=n;i++)
        for(int j=0;i<=2;j++){
            cmp=max(maxl[i][j],cmp);
        }

        cout<<cmp;
        return 0;
}