codeforces 1133D （map+精度控制）

#include<bits/stdc++.h>
#define x first
#define y second
#define PB push_back
#define mst(x,a) memset(x,a,sizeof(x))
#define all(a) begin(a),end(a)
#define rep(x,l,u) for(ll x=l;x<u;x++)
#define rrep(x,l,u) for(ll x=l;x>=u;x--)
#define sz(x) x.size()
#define IOS ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
typedef unsigned long long ull;
typedef pair<int,int> PII;
typedef pair<long,long> PLL;
typedef pair<char,char> PCC;
typedef long long ll;
const int N=2*1e5+10;
const int M=1e6+10;
const int INF=0x3f3f3f3f;
const int MOD=1e9+7;
int a[N],b[N];
void solve(){
    int n;scanf("%d",&n);
    rep(i,0,n) scanf("%d",&a[i]);
    rep(i,0,n) scanf("%d",&b[i]);
    map<PII,int> cnt;
    int f=0,ans=0,res=0;
    rep(i,0,n){
        if(!a[i] && !b[i]){
            res++;
            continue;
        }
        if(!a[i]) continue;
        if(!b[i]){
            cnt[{0,1}]++;
            continue;
        }
        int t=__gcd(a[i],b[i]);
        a[i]/=t;
        b[i]/=t;
        cnt[{b[i],a[i]}]++;
    }
    ans=max(ans,res+cnt[{0,1}]);
    for(auto p : cnt){
        ans=max(ans,p.y+res);
    }
    printf("%d\n",ans);
}
int main(){
    //IOS;
    //freopen("test.txt", "r", stdin);
    //freopen("test.txt", "w", stdout);
    //int t;cin>>t;
    //while(t--)
        solve();
    return 0;
}