MLE五个点，求助

#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll a[50005],b[50005];
ll n;
ll f[5005][5005];
int main(){
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    for(int i=1;i<=n;i++){
        cin>>b[i];
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            if(a[i]==b[j]) f[i][j]=f[i-1][j-1]+1;
            else f[i][j]=max(f[i-1][j],f[i][j-1]);
        }
    }
    cout<<f[n][n];
    return 0;
}