Submission #338535

#	Time	Username	Problem	Language	Result	Execution time	Memory
338535		kiennguyen246	Bulldozer (JOI17_bulldozer)	C++14	5 / 100	264 ms	512 KiB

bulldozer

/**
 * \author : Nguyen Duc Kien
 * \date : 23/12/2020
 * \version : 6.3.1
 */

///Task name
#define TASK "BULLDOZER"

/**--------------------------------------------------**/

#include <bits/stdc++.h>

#define int int64_t

using namespace std;

const int maxn = 2005;
const int infi = 1e9 + 69;

int n;
struct point
{
    int x, y, w;

    void inp()
    {
        cin >> x >> y >> w;
    }
}a[maxn];
struct line
{
    long long a, b, c;

    void make_line(point A, point B)
    {
        int ux = B.x - A.x;
        int uy = B.y - A.y;
        a = -uy, b = ux;
        c = a * A.x + b * A.y;
        c = -c;
    }

    ///Raw distance (without abs)
    double pos(point A)
    {
        return double(a * A.x + b * A.y + c) / hypot(abs(a), abs(b));
    }
}d;

bool by_x(point u, point v)
{
    return (u.x < v.x);
}

bool by_pos(point u, point v)
{
    return (d.pos(u) < d.pos(v));
}

namespace Sub1
{
    long long sx[maxn], res;

    void Main()
    {
        sort(a + 1, a + n + 1, by_x);
        for (int i = 1; i <= n; i ++)
            sx[i] = sx[i - 1] + a[i].w;
        for (int i = 1; i <= n; i ++)
            for (int j = i; j <= n; j ++)
                res = max(res, sx[j] - sx[i - 1]);
        cout << res;
    }
}

namespace Sub2
{
    point b[maxn];
    int w[maxn], cnt;

    void Main()
    {
        b[0] = {-180571500, 708072270, 0};
        long long res = 0;
        for (int i = 1; i <= n; i ++) res = max(res, 1ll * a[i].w);
        for (int i = 1; i <= n; i ++)
            for (int j = i + 1; j <= n; j ++)
            {
                d.make_line(a[i], a[j]);
                for (int t = 1; t <= n; t ++) b[t] = a[t];
                sort(b + 1, b + n + 1, by_pos);
                cnt = 0;
                memset(w, 0, sizeof(w));
                for (int k = 1; k <= n; k ++)
                {
                    if (abs(d.pos(b[k])) > 1e-18 || abs(d.pos(b[k - 1]))> 1e-18) w[++cnt] = b[k].w;
                    else w[cnt] += b[k].w;
                }
                long long cur = 0;
                for (int k = 1; k <= cnt; k ++)
                {
                    cur += w[k];
                    res = max(res, cur);
                    if (cur < 0) cur = 0;
                }
            }
        cout << res;

    }
}

int32_t main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	cerr << "Processing...\n\n";
	if (fopen(TASK".INP", "r"))
	{
		freopen(TASK".INP", "r", stdin);
		freopen(TASK".OUT", "w", stdout);
	}

	cin >> n;
	for (int i = 1; i <= n; i ++) a[i].inp();
	bool all_ox = 1;
	for (int i = 1; i <= n; i ++)
        if (a[i].y != 0) all_ox = 0;
    if (all_ox) Sub1::Main();
    else Sub2::Main();
	cerr << "\n\n--------------\n";
	return 0;
}

Compilation message (stderr)

bulldozer.cpp: In function 'int32_t main()':
bulldozer.cpp:120:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  120 |   freopen(TASK".INP", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bulldozer.cpp:121:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  121 |   freopen(TASK".OUT", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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