Submission #1261281

#	Time	Username	Problem	Language	Result	Execution time	Memory
1261281		kikitop1gg	Portal (BOI24_portal)	C++17	100 / 100	16 ms	4032 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vi vector<ll>
#define vvi vector<vector<ll>>
#define vs vector<string>
#define vc vector<char>
#define vb vector<bool>
#define vp vector<pair<ll, ll>>
#define vpp vector<pair<ll, pair<ll, ll>>>
#define pp pair<ll, ll>
#define qi queue<ll>
#define qp queue<pp>
#define pqi priority_queue<ll>
#define pqp priority_queue<pp>
#define mi map<ll, ll>
#define mpi map<pp, ll>
#define mip map<ll, pp>
#define mp map<pp, pp>
#define mb map<ll, bool>
#define si set<ll>
#define sp set<pp>
#define sc set<char>
#define mod 1000000007
#define inf INT_MAX
#define all(x) (x).begin(), (x).end()

ll cross(pp a, pp b) {
    return abs(a.first * b.second - a.second * b.first);
}

ll GCD(ll a, ll b) {
    if(b == 0) return a;
    return GCD(b, a % b);
}

pp vec_gcd(pp a, pp b) {
    return {GCD(a.first, b.first), GCD(a.second, b.second)};
}

pair<pp, pp> pal_gcd(pp a, pp b, pp c) {
    if(cross(a, b) == 0) {
        a = vec_gcd(a, b);
        b = c;
        return {a, b};
    }
    if(cross(a, c) == 0) {
        a = vec_gcd(a, c);
        return {a, b};
    }
    if(cross(b, c) == 0) {
        b = vec_gcd(b, c);
        return {a, b};
    }

    ll dem = a.first * b.second - a.second * b.first;
    ll k = (c.first * b.second - c.second * b.first) / dem;
    ll l = (a.first * c.second - a.second * c.first ) / dem;

    pp remainder;
    remainder.first = c.first - k * a.first - l * b.first;
    remainder.second = c.second - k * a.second - l * b.second;

    return pal_gcd(a, remainder, b);
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    ll n;
    cin >> n;
    vp ar(n);
    for(int i = 0; i < n; i++) {
        cin >> ar[i].first >> ar[i].second;
    }
    if(n <= 2) {
        cout << "-1\n";
        return 0;
    }

    vp v;
    for(int i = 1; i < n; i++) {
        ll x = ar[0].first - ar[i].first;
        ll y = ar[0].second - ar[i].second;
        v.push_back({x, y});
    }


    pp base;
    for(int i = 1; i < v.size(); i++) {
        if(v[i] == v[0]) {
            if(i + 1 == v.size()) {
                cout << "-1\n";
                return 0;
            }
            continue;
        }
        ll x = v[0].first - v[i].first;
        ll y = v[0].second - v[i].second;
        base = {x, y};
        break;
    }

    pp a = v[0];
    pp b;
    ll ans = 0;
    for(int i = 1; i < v.size(); i++) {
        swap(v[i], v[1]);
        b = v[1];
        ll cur = cross(a, b);
        ans = cur;
        if(ans != 0) {
            break;
        }
    }
    if(ans == 0) {
        cout << "-1\n";
        return 0;
    }

    for(int i = 2; i < v.size(); i++) {
        auto p = pal_gcd(a, b, v[i]);
        a = p.first;
        b = p.second;
    }

    ans = cross(a, b);
    cout << ans << '\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