Submission #538390

#	Time	Username	Problem	Language	Result	Execution time	Memory
538390		Sorting	The Forest of Fangorn (CEOI14_fangorn)	C++17	20 / 100	3060 ms	340 KiB

fangorn

#include <bits/stdc++.h>

using namespace std;

typedef long double ld;
typedef long long ll;
template<class T> void check_min(T &a, const T &b){ a = (a < b) ? a : b; }
template<class T> void check_max(T &a, const T &b){ a = (a > b) ? a : b; }
#define a__int128(x) (x).begin(), (x).end()

const ll N = 2000 + 3;
const ll C = 1e4 + 3;
const ll INF = 1e9;

ll n, c, w, h;
ll x, y;
pair<ll, ll> cp[C], tp[N];

__int128 orient(__int128 x1, __int128 y1, __int128 x2, __int128 y2, __int128 x3, __int128 y3){
    return x1 * y2 + x2 * y3 + x3 * y1 - x1 * y3 - x2 * y1 - x3 * y2;
}

__int128 sign(__int128 x){
    return (x == 0) ? 0 : ((x > 0) ? 1 : -1);
}

bool on_line(__int128 x1, __int128 y1, __int128 x2, __int128 y2, __int128 x3, __int128 y3){
    if(orient(x1, y1, x2, y2, x3, y3)) return false;
    return min(x1, x2) <= x3 && x3 <= max(x1, x2) && min(y1, y2) <= y3 && y3 <= max(y1, y2);
}

bool intersect(__int128 x1, __int128 y1, __int128 x2, __int128 y2, __int128 x3, __int128 y3, __int128 x4, __int128 y4){
    __int128 a1 = sign(orient(x1, y1, x2, y2, x3, y3));
    __int128 a2 = sign(orient(x1, y1, x2, y2, x4, y4));
    __int128 a3 = sign(orient(x3, y3, x4, y4, x1, y1));
    __int128 a4 = sign(orient(x3, y3, x4, y4, x2, y2));

    if(on_line(x1, y1, x2, y2, x3, y3) && on_line(x1, y1, x2, y2, x4, y4))
        return true;
    if(on_line(x3, y3, x4, y4, x1, y1) && on_line(x3, y3, x4, y4, x2, y2))
        return true;

    if(!a1 || !a2 || !a3 || !a4)
        return false;

    if(a1 != a2 && a3 != a4)
        return true;

    return false;
}

array<__int128, 4> segmentToLine(__int128 x1, __int128 y1, __int128 x2, __int128 y2){
    __int128 x3 = x1 + (x1 - x2) * INF;
    __int128 y3 = y1 + (y1 - y2) * INF;
    __int128 x4 = x2 + (x2 - x1) * INF;
    __int128 y4 = y2 + (y2 - y1) * INF;
    return array<__int128, 4>{x3, y3, x4, y4};
}

bool check(__int128 x1, __int128 y1, __int128 x2, __int128 y2){
    for(int i = 0; i < n; ++i){
        for(int j = i + 1; j < n; ++j){
            auto [x3, y3, x4, y4] = segmentToLine(tp[i].first, tp[i].second, tp[j].first, tp[j].second);
            bool in1 = intersect(x1, y1, x2, y2, tp[i].first, tp[i].second, tp[j].first, tp[j].second);
            bool in2 = intersect(x1, y1, x2, y2, x3, y3, x4, y4);
            if(in2){
                if(!in1){
                    return false;
                }
            }
        }
    }

    return true;
}

bool check2(__int128 x, __int128 y){
    for(int i = 0; i < n; ++i){
        for(int j = i + 1; j < n; ++j){
            if(orient(tp[i].first, tp[i].second, tp[j].first, tp[j].second, x, y) == 0){
                if(!on_line(tp[i].first, tp[i].second, tp[j].first, tp[j].second, x, y))
                    return false;
            }
        }
    }

    return true;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> w >> h >> x >> y;

    cin >> c;
    for(int i = 0; i < c; ++i){
        cin >> cp[i].first >> cp[i].second;
    }

    cin >> n;
    for(int i = 0; i < n; ++i){
        cin >> tp[i].first >> tp[i].second;
    }

    __int128 midx = 0, midy = 0;
    for(int i = 0; i < n; ++i){
        midx += tp[i].first;
        midy += tp[i].second;
    }

    midx /= n;
    midy /= n;

    vector<int> ans;
    for(int i = 0; i < c; ++i){
        if(!check2(cp[i].first, cp[i].second))
            continue;

        if(check(x, y, cp[i].first, cp[i].second))
            ans.push_back(i + 1);
        else if(check(x, y, midx, midy) && check(midx, midy, cp[i].first, cp[i].second))
            ans.push_back(i + 1);
    }

    cout << ans.size() << "\n";
    for(int x: ans)
        cout << x << " ";
    cout << "\n";
}

• Subtask 1: 0 / 30
• Subtask 2: 20 / 20
• Subtask 3: 0 / 30
• Subtask 4: 0 / 20