結果

問題 No.947 ABC包囲網
コンテスト
ユーザー ianCK
提出日時 2019-12-10 18:12:04
言語 C++11（廃止可能性あり）
(gcc 13.3.0)
結果
WA  
実行時間 -
コード長 2,379 bytes
コンパイル時間 821 ms
コンパイル使用メモリ 48,580 KB
実行使用メモリ 6,948 KB
最終ジャッジ日時 2024-06-24 02:02:06
合計ジャッジ時間 57,442 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 4 WA * 5 RE * 28 TLE * 23
権限があれば一括ダウンロードができます
コンパイルメッセージ
main.cpp: In member function ‘void Point::in()’:
main.cpp:17:27: warning: format ‘%lld’ expects argument of type ‘long long int*’, but argument 2 has type ‘ll*’ {aka ‘__int128*’} [-Wformat=]
   17 |                 scanf("%lld%lld", &x, &y);
      |                        ~~~^       ~~
      |                           |       |
      |                           |       ll* {aka __int128*}
      |                           long long int*
main.cpp:17:31: warning: format ‘%lld’ expects argument of type ‘long long int*’, but argument 3 has type ‘ll*’ {aka ‘__int128*’} [-Wformat=]
   17 |                 scanf("%lld%lld", &x, &y);
      |                            ~~~^       ~~
      |                               |       |
      |                               |       ll* {aka __int128*}
      |                               long long int*
main.cpp: In member function ‘void Point::out()’:
main.cpp:21:28: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 2 has type ‘ll’ {aka ‘__int128’} [-Wformat=]
   21 |                 printf("%lld %lld\n", x, y);
      |                         ~~~^          ~
      |                            |          |
      |                            |          ll {aka __int128}
      |                            long long int
main.cpp:21:33: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 3 has type ‘ll’ {aka ‘__int128’} [-Wformat=]
   21 |                 printf("%lld %lld\n", x, y);
      |                              ~~~^        ~
      |                                 |        |
      |                                 |        ll {aka __int128}
      |                                 long long int
main.cpp: In function ‘ll cnt(int)’:
main.cpp:87:37: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 2 has type ‘ll’ {aka ‘__int128’} [-Wformat=]
   87 |

ソースコード

diff # 

bool debug = false;
#include <stdio.h>
#include <assert.h>
#include <algorithm>
#include <vector>
using namespace std;

typedef __int128 ll;
constexpr int kN = int(4E3 + 10), kInf = int(1E9 + 10);
#define PB push_back

struct Point {
	ll x, y;
	Point(ll a, ll b) {x = a, y = b;}
	Point() {}
	void in() {
		scanf("%lld%lld", &x, &y);
		return ;
	}
	void out() {
		printf("%lld %lld\n", x, y);
		return ;
	}
	Point operator -(Point b) const {return Point(x - b.x, y - b.y);}
	ll operator ^(Point b) const {return x * b.y - y * b.x;}
};


const Point O(0, 0);

int dcmp(ll x) {return x > 0 ? 1 : x == 0 ? 0 : -1;}

bool segment_intersection(Point p1, Point p2, Point p3, Point p4) {
	if (debug) {
		printf("p1::"); p1.out();
		printf("p2::"); p2.out();
		printf("p3::"); p3.out();
		printf("p4::"); p4.out();
		printf("intersect? %d\n", dcmp((p2 - p1) ^ (p3 - p1)) * dcmp((p2 - p1) ^ (p4 - p1)));
		printf("intersect? %d\n", dcmp((p4 - p3) ^ (p1 - p3)) * dcmp((p4 - p3) ^ (p2 - p3)));
	}
	return dcmp((p2 - p1) ^ (p3 - p1)) * dcmp((p2 - p1) ^ (p4 - p1)) <= 0 &&
		dcmp((p4 - p3) ^ (p1 - p3)) * dcmp((p4 - p3) ^ (p2 - p3)) <= 0;
}

int n;
Point p[kN];



ll cnt(int x) {
	vector<int> left, right;
	Point now(-p[x].x * kInf, -p[x].y * kInf);
	int lpos = 0, rpos = 0, lsz, rsz;
	ll ans = 0, tmp;
	for (int i = 1; i <= n; i++) if (i != x) {
		tmp = p[i] ^ p[x];
		if (tmp < 0) left.PB(i);
		else if (tmp > 0) right.PB(i);
	}	

	auto cmp = [&](int a, int b) {return (p[a] ^ p[b]) > 0;};
	sort(left.begin(), left.end(), cmp);
	sort(right.begin(), right.end(), cmp);
	
	lsz = int(left.size());
	rsz = int(right.size());
	
	if (debug) {
		printf("x = %d\n", x);
		printf("-- left --\n");
		for (int i : left) printf("%d\n", i);
		printf("-- right --\n");
		for (int i : right) printf("%d\n", i);
	}
	
	while (lpos < lsz) {
		while (rpos < rsz) {
			if (!segment_intersection(p[left[lpos]], p[right[rpos]], now, O)) rpos++;
			else break;
		}
		if (debug) printf("lpos = %d, rpos = %d\n", lpos, rpos);
		ans += rpos;
		lpos++;
	}

	if (debug) printf("ans = %lld\n", ans);
	
	return ans;
}

int main() {
	ll ans = 0;
	scanf("%d", &n);
	for (int i = 1; i <= n; i++) p[i].in();

	for (int i = 1; i <= n; i++) ans += cnt(i);	
	assert(ans % 3 == 0);
	printf("%lld\n", (long long int) ans / 3);
}
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