oj.uz

답안 #545880

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
545880 2022-04-05T15:49:52 Z rainboy Printed Circuit Board (CEOI12_circuit) C
85 / 100
 100 ms 6108 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_;
 
int lt(int i, int j) {
	int i0 = ii[i << 1 | 0], i1 = ii[i << 1 | 1], j0 = ii[j << 1 | 0], j1 = ii[j << 1 | 1];
 
	return cross(i0, i1, j0) >= 0 && cross(i0, i1, j1) >= 0 || cross(j0, j1, i0) <= 0 && cross(j0, j1, i1) <= 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 'lt':
circuit.c:55:32: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   55 |  return cross(i0, i1, j0) >= 0 && cross(i0, i1, j1) >= 0 || cross(j0, j1, i0) <= 0 && cross(j0, j1, i1) <= 0;
      |         ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
circuit.c: In function 'main':
circuit.c:97:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
circuit.c:99:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |   scanf("%d%d", &xx[i], &yy[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
85.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 2 ms 384 KB Output is correct
4 Correct 2 ms 340 KB Output is correct
5 Correct 7 ms 596 KB Output is correct
6 Correct 8 ms 596 KB Output is correct
7 Correct 15 ms 852 KB Output is correct
8 Correct 6 ms 468 KB Output is correct
9 Correct 7 ms 584 KB Output is correct
10 Correct 7 ms 596 KB Output is correct
11 Correct 10 ms 640 KB Output is correct
12 Correct 10 ms 840 KB Output is correct
13 Correct 21 ms 1188 KB Output is correct
14 Correct 21 ms 1444 KB Output is correct
15 Correct 27 ms 1608 KB Output is correct
16 Correct 54 ms 3100 KB Output is correct
17 Correct 73 ms 3152 KB Output is correct
18 Execution timed out 105 ms 5896 KB Time limit exceeded
19 Execution timed out 111 ms 5912 KB Time limit exceeded
20 Execution timed out 155 ms 6108 KB Time limit exceeded