Submission #46855

#	Time	Username	Problem	Language	Result	Execution time	Memory
46855		qoo2p5	Bulldozer (JOI17_bulldozer)	C++17	100 / 100	942 ms	63388 KiB

bulldozer

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int INF = (int) 1e9 + 1e6;
const ll LINF = (ll) 1e18 + 1e9;
const ll MOD = (ll) 1e9 + 7;

#define sz(x) (int) (x).size()
#define mp(x, y) make_pair(x, y)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lb(s, t, x) (int) (lower_bound(s, t, x) - s)
#define ub(s, t, x) (int) (upper_bound(s, t, x) - s)
#define rep(i, f, t) for (auto i = f; i < t; ++(i))
#define per(i, f, t) for (auto i = (f); i >= (t); --(i))

ll power(ll x, ll y, ll mod = MOD) {
    if (y == 0) {
        return 1;
    }
    if (y & 1) {
        return power(x, y - 1, mod) * x % mod;
    } else {
        ll tmp = power(x, y / 2, mod);
        return tmp * tmp % mod;
    }
}

template<typename A, typename B> bool mini(A &x, const B &y) {
    if (y < x) {
        x = y;
        return true;
    }
    return false;
}

template<typename A, typename B> bool maxi(A &x, const B &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

void add(ll &x, ll y) {
    x += y;
    if (x >= MOD) x -= MOD;
    if (x < 0) x += MOD;
}

void run();

#define TASK ""

int main() {
#ifdef LOCAL
    if (strlen(TASK) > 0) {
        cerr << "Reminder: you are using file i/o, filename: " TASK "!" << endl << endl;
    }
#endif
#ifndef LOCAL
    if (strlen(TASK)) {
        freopen(TASK ".in", "r", stdin);
        freopen(TASK ".out", "w", stdout);
    }
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
#endif
    cout << fixed << setprecision(12);
    run();
    return 0;
}

// == SOLUTION == //

#define double long double

const int N = 1 << 11;
const double EPS = 1e-16;

struct P {
	ll x, y, c;
};

int n;
P p[N];

struct F {
	bool is_inf;
	ll p, q;
	
	F() {}
	
	F(ll pp, ll qq) {
		p = 0;
		q = 0;
		is_inf = 0;
		if (qq == 0) {
			is_inf = 1;
		} else {
			p = pp;
			q = qq;
			if (q < 0) {
				p = -p;
				q = -q;
			}
		}
	}
	
	bool operator<(const F &b) const {
		return mp(is_inf, p * b.q) < mp(b.is_inf, b.p * q);
	}
};

struct Ev {
	int a, b;
	F ang;
	
	Ev(int a, int b) : a(a), b(b) {
		ang = F(p[a].y - p[b].y, p[a].x - p[b].x);
	}
};

bool operator<(const Ev &u, const Ev &v) {
	if (u.ang < v.ang) {
		return 1;
	}
	if (v.ang < u.ang) {
		return 0;
	}
	
	return mp(u.a, u.b) < mp(v.a, v.b);
}

struct Node {
	ll sum, res, left, right;
};

Node tree[2 * N + 13];

void upd(int i, ll val) {
	i += N;
	tree[i] = {val, max(0LL, val), max(0LL, val), max(0LL, val)};
	i /= 2;
	while (i > 0) {
		tree[i].sum = tree[2 * i].sum + tree[2 * i + 1].sum;
		tree[i].left = max(tree[2 * i].left, tree[2 * i].sum + tree[2 * i + 1].left);
		tree[i].right = max(tree[2 * i + 1].right, tree[2 * i + 1].sum + tree[2 * i].right);
		tree[i].res = max(tree[2 * i].right + tree[2 * i + 1].left, max(tree[2 * i].res, tree[2 * i + 1].res));
		i /= 2;
	}
}

ll get() {
	return tree[1].res;
}

int pos[N];

void make(const Ev &ev) {
	int a = pos[ev.a];
	int b = pos[ev.b];
	assert(a + 1 == b);
	swap(pos[ev.a], pos[ev.b]);
	ll va = tree[N + a].sum;
	ll vb = tree[N + b].sum;
	upd(a, vb);
	upd(b, va);
}

void run() {
	cin >> n;
	rep(i, 0, n) {
		cin >> p[i].x >> p[i].y >> p[i].c;
	}
	sort(p, p + n, [] (const auto &a, const auto &b) {
		return mp(a.x, a.y) < mp(b.x, b.y);
	});
	vector<Ev> events;
	events.reserve(n * (n - 1) / 2);
	rep(i, 0, n) {
		rep(j, i + 1, n) {
			events.pb(Ev(i, j));
		}
	}
	sort(all(events));
	
	ll ans = 0;
	rep(i, 0, n) {
		upd(i, p[i].c);
		pos[i] = i;
	}
	
	maxi(ans, get());
	
	rep(i, 0, sz(events)) {
		make(events[i]);
		int j = i;
		while (j + 1 < sz(events) && !(events[j].ang < events[j + 1].ang)) {
			j++;
			make(events[j]);
		}
		
		maxi(ans, get());
		i = j;
	}
	
	cout << ans << "\n";
}

Compilation message (stderr)

bulldozer.cpp: In function 'int main()':
bulldozer.cpp:67:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(TASK ".in", "r", stdin);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bulldozer.cpp:68:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(TASK ".out", "w", stdout);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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