Submission #1077807

#	Time	Username	Problem	Language	Result	Execution time	Memory
1077807		danikoynov	Bulldozer (JOI17_bulldozer)	C++14	20 / 100	2036 ms	856 KiB

bulldozer

#include<bits/stdc++.h>
#define endl '\n'
    
using namespace std;
typedef long long ll;
    
struct Point
{
    ll x, y;
    
    Point(ll _x = 0, ll _y = 0)
    {
        x = _x;
        y = _y;
    }
    
    void input()
    {
        cin >> x >> y;
    }
};
    
const int MAXN = 2010;
int n;
pair < Point, ll > spot[MAXN];
void input()
{
    cin >> n;
    for (int i = 1; i <= n; i ++)
    {
        spot[i].first.input();
        cin >> spot[i].second;
    }
}
    
ll signed_area(Point A, Point B, Point C) /// returns signed area * 2
{
    ll area = (B.x - A.x) * (A.y + B.y) +
                (C.x - B.x) * (B.y + C.y) +
                    (A.x - C.x) * (C.y + A.y);
    return area;
}
    
int orient(Point A, Point B, Point C)
{
    
    ll area = signed_area(A, B, C);
    
    if (area > 0)
        return 1;
    if (area < 0)
        return -1;
    assert(area != 0);
    return 0;
}
    
void simulate()
{
    
    bool all_x = true;
    for (int i = 1; i <= n; i ++)
        if (spot[i].first.y != 0)
            all_x = false;
    ll result = 0;
    if (all_x)
    {
        for (int i = 1; i <= n; i ++)
            if (spot[i].second > 0)
                result += spot[i].second;
        cout << result << endl;
        return;
    }

    if (n == 1)
    {
        result = max(result, spot[1].second);
    }
    if (n == 2)
    {
        result = max(result, spot[1].second);
        result = max(result, spot[2].second);
        result = max(result, spot[1].second + spot[2].second);
    }
    for (int i = 1; i <= n; i ++)
        for (int j = i + 1; j <= n; j ++)
        {
            vector < pair < ll, ll > > pos, neg;
            for (int k = 1; k <= n; k ++)
            {
                if (k == i || k == j)
                    continue;
                ll area = signed_area(spot[i].first, 
                                        spot[j].first, 
                                        spot[k].first);
                /**if (i == 3 && j == 4)
                {
                    cout << "pair with " << k << " area " << area << " value " << spot[k].second << endl;
                }*/
                assert(area != 0);
                if (area > 0)
                    pos.push_back({area, spot[k].second});
                else
                    neg.push_back({-area, spot[k].second});
                
            }
    
            sort(pos.begin(), pos.end());
            sort(neg.begin(), neg.end());
    
            ll best = 0, sum = 0;
            ll ls = -1;
            for (pair < ll, ll > cur : pos)
            {
                sum += cur.second;
                assert(cur.first != ls);
                ls = cur.first;
                best = max(best, sum);
            }
            ls = -1;
            sum = 0;
            for (pair < ll, ll > cur : neg)
            {
                sum += cur.second;
                assert(cur.first != ls);
                ls = cur.first;
                best = max(best, sum);
            }

            //cout << "HERE " << best << endl;
            best = best + spot[i].second;
            best = best + spot[j].second;
            //cout << "new best " << best << endl;
            //ll mx = min(spot[i].second, spot[j].second);
            //cout << "mx " << mx << endl;
            if (spot[i].second < 0)
                best -= spot[i].second;
            if (spot[j].second < 0)
                best -= spot[j].second;
            //cout << "pair " << i << " " << j << " " << best << endl;
            result = max(result, best);
    
        }
    
    cout << result << endl;
}
void solve()
{
    input();
    simulate();
}
int main()
{
    solve();
    return 0;
}
/*
3
0 0 1
1 0 1
2 0 1
*/

• Subtask 1: 0 / 5
• Subtask 2: 20 / 20
• Subtask 3: 0 / 35
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20