Submission #1045042

#	Time	Username	Problem	Language	Result	Execution time	Memory
1045042		owoovo	Portal (BOI24_portal)	C++17	100 / 100	21 ms	13776 KiB

Main

#include <bits/stdc++.h>
#define ll __int128_t
#define pll pair<ll,ll>
#define F first
#define S second
 
using namespace std;
const ll zo=0;

vector<pll> point,vc;
long long n;
ll abs2(ll a){
    return max(a,-a);
}
ll gcd2(ll a,ll b){
    if(b==0)return a;
    return gcd2(b,a%b);
}
pll fd(pll a){
    return max(a,{-a.F,-a.S});
}
void _gcd(pll &a,pll &b){
    if(a.F==0||b.F==0)return;
    if(a.F<b.F)swap(a,b);
    ll g=a.F/b.F;
    a.F-=b.F*g;
    a.S-=b.S*g;
    _gcd(b,a);
    return ;
}
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin>>n;
    for(int i=0;i<n;i++){
        long long x,y;
        cin>>x>>y;
        point.push_back({x,y});
    }
    for(int i=1;i<n;i++){
        vc.push_back(fd({point[i].F-point[0].F,point[i].S-point[0].S}));
    }
    pll now={0,0};
    vector<ll> s;
    for(int i=0;i<n-1;i++){
        if(vc[i].F==0){
            s.push_back(vc[i].S);
        }else{
            if(now==make_pair(zo,zo)){
                now=vc[i];
            }else{
                _gcd(now,vc[i]);
                if(now.F==0)swap(now,vc[i]);
                s.push_back(vc[i].S);
            }
        }

    }
    ll sg=0;
    int len=s.size();
    for(int i=0;i<len;i++){
        if(s[i]!=0){
            if(sg==zo)sg=abs2(s[i]);
            else sg=gcd2(sg,abs2(s[i]));
        }
    }
    if(now.F==0||sg==0){
        cout<<"-1\n";
    }else{
        cout<<(long long)(now.F*sg)<<"\n";
    }
    return 0;
}

• Subtask 1: 1 / 1
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 29 / 29
• Subtask 5: 15 / 15
• Subtask 6: 35 / 35