oj.uz

답안 #544793

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
544793 2022-04-02T16:51:38 Z rainboy Printed Circuit Board (CEOI12_circuit) C
85 / 100
 100 ms 8784 KB 
#include <stdio.h>
#include <string.h>
 
#define N	200000
 
unsigned int X = 12345;
 
int rand_() {
	return (X *= 3) >> 1;
}
 
long long cross2(int x1, int y1, int x2, int y2) {
	return (long long) x1 * y2 - (long long) x2 * y1;
}
 
int xx[N], yy[N], ii[N * 2];
 
long long cross(int i, int j, int k) {
	return cross2(xx[j] - xx[i], yy[j] - yy[i], xx[k] - xx[i], yy[k] - yy[i]);
}
 
int cmp(int h1, int h2) {
	long long c = cross2(xx[ii[h1]], yy[ii[h1]], xx[ii[h2]], yy[ii[h2]]);
 
	return c ? (c < 0 ? -1 : 1) : (h1 & 1) - (h2 & 1);
}
 
void sort(int *hh, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, h_ = hh[l + rand_() % (r - l)], tmp;
 
		while (j < k) {
			int c = cmp(hh[j], h_);
 
			if (c == 0)
				j++;
			else if (c < 0) {
				tmp = hh[i], hh[i] = hh[j], hh[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = hh[j], hh[j] = hh[k], hh[k] = tmp;
			}
		}
		sort(hh, l, i);
		l = k;
	}
}
 
int iq[1 + N], pq[N], cnt, x_, y_;
 
double t(int i, int j) {
	return (double) cross2(xx[i], yy[i], xx[j] - xx[i], yy[j] - yy[i]) / cross2(x_, y_, xx[j] - xx[i], yy[j] - yy[i]);
}
 
int lt(int i, int j) {
	double t1 = t(ii[i << 1 | 0], ii[i << 1 | 1]), t2 = t(ii[j << 1 | 0], ii[j << 1 | 1]);
 
	if (t1 != t2)
		return t1 < t2;
	return cross(ii[i << 1 | 0], ii[j << 1 | 0], ii[j << 1 | 1]) < 0 || cross(ii[i << 1 | 1], ii[j << 1 | 0], ii[j << 1 | 1]) < 0;
}
 
int p2(int p) {
	return (p *= 2) > cnt ? 0 : (p < cnt && lt(iq[p + 1], iq[p]) ? p + 1 : p);
}
 
void pq_up(int i) {
	int p, q, j;
 
	for (p = pq[i]; (q = p / 2) && lt(i, j = iq[q]); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}
 
void pq_dn(int i) {
	int p, q, j;
 
	for (p = pq[i]; (q = p2(p)) && lt(j = iq[q], i); p = q)
		iq[pq[j] = p] = j;
	iq[pq[i] = p] = i;
}
 
void pq_add(int i) {
	pq[i] = ++cnt, pq_up(i);
}
 
void pq_remove(int i) {
	if (pq[i]) {
		int j = iq[cnt--];
 
		if (j != i)
			pq[j] = pq[i], pq_up(j), pq_dn(j);
		pq[i] = 0;
	}
}
 
int main() {
	static int hh[N * 2];
	static char visible[N];
	int n, n_, g, h, h_, i;
 
	scanf("%d", &n);
	for (i = 0; i < n; i++)
		scanf("%d%d", &xx[i], &yy[i]);
	n_ = 0;
	for (i = 0; i < n; i++) {
		long long c = cross2(xx[i], yy[i], xx[(i + 1) % n], yy[(i + 1) % n]);
 
		if (c < 0) {
			ii[i << 1 | 0] = i, ii[i << 1 | 1] = (i + 1) % n;
			hh[n_++] = i << 1 | 0, hh[n_++] = i << 1 | 1;
		} else if (c > 0) {
			ii[i << 1 | 0] = (i + 1) % n, ii[i << 1 | 1] = i;
			hh[n_++] = i << 1 | 0, hh[n_++] = i << 1 | 1;
		}
	}
	sort(hh, 0, n_);
	memset(visible, 1, n * sizeof *visible);
	for (h = 0; h < n_; h++) {
		h_ = hh[h];
		x_ = xx[ii[h_]], y_ = yy[ii[h_]];
		if ((h_ & 1) == 0)
			pq_add(h_ >> 1);
		else
			pq_remove(h_ >> 1);
		if (cnt) {
			i = iq[1];
			if (cross(ii[i << 1 | 0], ii[i << 1 | 1], ii[h_]) > 0)
				visible[ii[h_]] = 0;
		}
	}
	for (h = 0; h < n_; h = h_) {
		int h1, i_;
 
		h1 = hh[h], h_ = h, i_ = -1;
		while (h_ < n_ && cross2(xx[ii[h1]], yy[ii[h1]], xx[ii[hh[h_]]], yy[ii[hh[h_]]]) == 0) {
			i = ii[hh[h_++]];
			if (i_ == -1 || xx[i_] > xx[i])
				i_ = i;
		}
		for (g = h; g < h_; g++) {
			i = ii[hh[g]];
			if (i != i_)
				visible[i] = 0;
		}
	}
	cnt = 0;
	for (i = 0; i < n; i++)
		if (visible[i])
			cnt++;
	printf("%d\n", cnt);
	for (i = 0; i < n; i++)
		if (visible[i])
			printf("%d ", i + 1);
	printf("\n");
	return 0;
}

Compilation message

circuit.c: In function 'main':
circuit.c:103:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  103 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
circuit.c:105:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |   scanf("%d%d", &xx[i], &yy[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
85.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 2 ms 340 KB Output is correct
4 Correct 4 ms 468 KB Output is correct
5 Correct 9 ms 724 KB Output is correct
6 Correct 9 ms 692 KB Output is correct
7 Correct 17 ms 1108 KB Output is correct
8 Correct 6 ms 568 KB Output is correct
9 Correct 7 ms 596 KB Output is correct
10 Correct 7 ms 684 KB Output is correct
11 Correct 8 ms 776 KB Output is correct
12 Correct 11 ms 992 KB Output is correct
13 Correct 24 ms 1532 KB Output is correct
14 Correct 26 ms 1804 KB Output is correct
15 Correct 30 ms 2272 KB Output is correct
16 Correct 60 ms 4336 KB Output is correct
17 Correct 78 ms 4548 KB Output is correct
18 Execution timed out 114 ms 8356 KB Time limit exceeded
19 Execution timed out 114 ms 8440 KB Time limit exceeded
20 Execution timed out 220 ms 8784 KB Time limit exceeded