Submission #480534

#	Time	Username	Problem	Language	Result	Execution time	Memory
480534		rainboy	Zvijezda (COCI19_zvijezda)	C11	0 / 110	2 ms	332 KiB

zvijezda

#include <stdio.h>

#define N	2000
#define eps	1e-6

long double abs_(long double a) { return a > 0 ? a : -a; }

long double cross(long long x0, long long y0, long long x1, long long y1, long long x2, long long y2) {
	return (long double) (x1 - x0) * (y2 - y0) - (long double) (x2 - x0) * (y1 - y0);
}

int main() {
	static int xx[N], yy[N];
	int n, q, online, i, k;

	scanf("%d%d", &online, &n);
	for (i = 0; i < n; i++)
		scanf("%d%d", &xx[i], &yy[i]);
	scanf("%d", &q);
	k = 0;
	while (q--) {
		long long x, y;
		int cnt;

		scanf("%lld%lld", &x, &y);
		if (online)
			x ^= (long long) k * k * k, y ^= (long long) k * k * k;
		cnt = 0;
		for (i = 0; i < n; i++) {
			long double c = cross(x, y, xx[i], yy[i], xx[(i + 1) % n], yy[(i + 1) % n]);

			if (c < 0)
				cnt++;
			else if (abs_(c) < eps) {
				cnt = 0;
				break;
			}
		}
		if (cnt < n / 2)
			printf("DA\n"), k++;
		else
			printf("NE\n");
	}
	return 0;
}

Compilation message (stderr)

zvijezda.c: In function 'main':
zvijezda.c:16:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |  scanf("%d%d", &online, &n);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~
zvijezda.c:18:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |   scanf("%d%d", &xx[i], &yy[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
zvijezda.c:19:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |  scanf("%d", &q);
      |  ^~~~~~~~~~~~~~~
zvijezda.c:25:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |   scanf("%lld%lld", &x, &y);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 30
• Subtask 3: 0 / 60