#522681 (C++14) No.1144 Triangles

• 問題: No.1144 Triangles
• ユーザー: nikkukun
• 提出日時: 2020-07-31 23:58:24
• 言語: C++14 (gcc 12.3.0 + boost 1.83.0)
• 結果: AC
• 実行時間: 591 ms / 3,000 ms
• コード長: 1,904 bytes
• コンパイル時間: 1,964 ms
• コンパイル使用メモリ: 176,888 KB
• 実行使用メモリ: 5,376 KB
• 最終ジャッジ日時: 2024-07-06 22:22:25
• 合計ジャッジ時間: 9,822 ms
• ジャッジサーバーID （参考情報）: judge2 / judge1

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	2 ms; 5,248 KB
testcase_01	AC	2 ms; 5,376 KB
testcase_02	AC	2 ms; 5,376 KB
testcase_03	AC	2 ms; 5,376 KB
testcase_04	AC	591 ms; 5,376 KB
testcase_05	AC	579 ms; 5,376 KB
testcase_06	AC	583 ms; 5,376 KB
testcase_07	AC	583 ms; 5,376 KB
testcase_08	AC	581 ms; 5,376 KB
testcase_09	AC	2 ms; 5,376 KB
testcase_10	AC	2 ms; 5,376 KB
testcase_11	AC	2 ms; 5,376 KB
testcase_12	AC	2 ms; 5,376 KB
testcase_13	AC	2 ms; 5,376 KB
testcase_14	AC	541 ms; 5,376 KB
testcase_15	AC	534 ms; 5,376 KB
testcase_16	AC	565 ms; 5,376 KB
testcase_17	AC	571 ms; 5,376 KB
testcase_18	AC	561 ms; 5,376 KB
testcase_19	AC	41 ms; 5,376 KB
testcase_20	AC	4 ms; 5,376 KB
testcase_21	AC	4 ms; 5,376 KB
testcase_22	AC	546 ms; 5,376 KB
testcase_23	AC	29 ms; 5,376 KB
testcase_24	AC	537 ms; 5,376 KB
testcase_25	AC	189 ms; 5,376 KB
testcase_26	AC	17 ms; 5,376 KB
testcase_27	AC	15 ms; 5,376 KB
testcase_28	AC	90 ms; 5,376 KB

ソースコード

// 21:50 - 22:02
#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define lch (o << 1)
#define rch (o << 1 | 1)

typedef double db;
typedef long long ll;
typedef unsigned int ui;
typedef pair<int, int> pint;
typedef tuple<int, int, int> tint;

const int N = 2000 + 5;
const int MOD = 1e9 + 7;
const int INV3 = 333333336;
const int INF = 0x3f3f3f3f;
const ll INF_LL = 0x3f3f3f3f3f3f3f3f;

struct Point {
	ll x, y;
	Point operator+(Point rhs) {
		return (Point){(x + rhs.x) % MOD, (y + rhs.y) % MOD};
	}
	Point operator-(Point rhs) {
		return (Point){(x - rhs.x) % MOD, (y - rhs.y) % MOD};
	}
	ll operator*(Point rhs) {
		return (x * rhs.y - y * rhs.x) % MOD;
	}
	bool operator==(Point rhs) {
		return x == rhs.x && y == rhs.y;
	}
};
Point p[N];

int n;

ll Solve(int rt) {
	vector<pair<double, Point>> _pts;
	for (int i = 1; i <= n; i++)
		if (i != rt) {
			auto tmp = p[i] - p[rt];
			if (tmp.x != 0 || tmp.y != 0)
				_pts.push_back(make_pair(atan2(tmp.y, tmp.x), tmp));
		}
	sort(all(_pts), [](pair<double, Point> &a, pair<double, Point> &b) {
		return a.fi < b.fi;
	});

	int m = _pts.size();
	vector<Point> pts;
	for (int i = 0; i < m; i++)
		pts.push_back(_pts[i].se);
	for (int i = 0; i < m; i++)
		pts.push_back(_pts[i].se);

	Point sum = (Point){0, 0};
	ll ret = 0, pre = 0;
	int r = 0;
	for (int i = 0; i < m; i++) {
		if (i == 0 || !(pts[i] == pts[i - 1])) {
			while (r < i + m && pts[i] * pts[r] >= 0) {
				sum = sum + pts[r];
				r++;
			}
			pre = pts[i] * sum;
		}
		ret = (ret + pre) % MOD;
		sum = sum - pts[i];
	}

	return ret;
}

int main() {
	ios::sync_with_stdio(0);

	cin >> n;
	for (int i = 1; i <= n; i++)
		cin >> p[i].x >> p[i].y;

	ll ans = 0;
	for (int i = 1; i <= n; i++) {
		ll tmp = Solve(i);
		ans = (ans + tmp) % MOD;
	}
	ans = ans * INV3 % MOD;

	cout << (ans % MOD + MOD) % MOD << endl;

	return 0;
}