Submission #224604

#TimeUsernameProblemLanguageResultExecution timeMemory
224604dolphingarlicBulldozer (JOI17_bulldozer)C++14
100 / 100
1060 ms47612 KiB
#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;

struct Node {
	ll l, r, tot, best;

	Node operator+(Node B) {
		return {max(l, tot + B.l), max(B.r, r + B.tot), tot + B.tot, max(max(best, B.best), r + B.l)};
	}
} segtree[8001];

struct Point {
	ll x, y, v;

	bool operator<(Point B) {
		if (x == B.x) return y < B.y;
		return x < B.x;
	}
} points[2001];

struct Line {
	ll dx, dy;
	int u, v;

	bool operator<(Line B) {
		if (dy * B.dx == B.dy * dx) return tie(u, v) < tie(B.u, B.v);
		return dy * B.dx < B.dy * dx;
	}
} swaps[2000001];

int n, curr[2001];

void build(int node = 1, int l = 1, int r = n) {
	if (l == r) {
		ll v = max(points[l].v, 0ll);
		segtree[node] = {v, v, points[l].v, v};
	} else {
		int mid = (l + r) / 2;
		build(node * 2, l, mid);
		build(node * 2 + 1, mid + 1, r);
		segtree[node] = segtree[node * 2] + segtree[node * 2 + 1];
	}
}

void update(int pos, ll val, int node = 1, int l = 1, int r = n) {
	if (l == r) segtree[node] = {max(val, 0ll), max(val, 0ll), val, max(val, 0ll)};
	else {
		int mid = (l + r) / 2;
		if (pos > mid) update(pos, val, node * 2 + 1, mid + 1, r);
		else update(pos, val, node * 2, l, mid);
		segtree[node] = segtree[node * 2] + segtree[node * 2 + 1];
	}
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin >> n;
	FOR(i, 1, n + 1) {
		cin >> points[i].x >> points[i].y >> points[i].v;
		curr[i] = i;
	}
	sort(points + 1, points + n + 1);
	int cnt = 0;
	FOR(i, 1, n + 1) FOR(j, i + 1, n + 1)
		swaps[cnt++] = {points[j].x - points[i].x, points[j].y - points[i].y, i, j};
	sort(swaps, swaps + cnt);

	build();
	ll ans = segtree[1].best;
	FOR(i, 0, cnt) {
		update(curr[swaps[i].u], points[swaps[i].v].v);
		update(curr[swaps[i].v], points[swaps[i].u].v);
		swap(curr[swaps[i].u], curr[swaps[i].v]);

		if (i == cnt - 1) ans = max(ans, segtree[1].best);
		else if (swaps[i].dy * swaps[i + 1].dx != swaps[i + 1].dy * swaps[i].dx) ans = max(ans, segtree[1].best);
	}
	cout << ans;
	return 0;
}
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