oj.uz

답안 #544794

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
544794 2022-04-02T16:52:49 Z rainboy Printed Circuit Board (CEOI12_circuit) C
85 / 100
 100 ms 6012 KB 
#pragma GCC optimize("O3")
#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:104:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  104 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
circuit.c:106:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |   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 340 KB Output is correct
4 Correct 3 ms 340 KB Output is correct
5 Correct 7 ms 596 KB Output is correct
6 Correct 7 ms 552 KB Output is correct
7 Correct 14 ms 788 KB Output is correct
8 Correct 7 ms 492 KB Output is correct
9 Correct 7 ms 596 KB Output is correct
10 Correct 8 ms 596 KB Output is correct
11 Correct 9 ms 596 KB Output is correct
12 Correct 11 ms 820 KB Output is correct
13 Correct 22 ms 1140 KB Output is correct
14 Correct 22 ms 1396 KB Output is correct
15 Correct 27 ms 1620 KB Output is correct
16 Correct 55 ms 3132 KB Output is correct
17 Correct 75 ms 3156 KB Output is correct
18 Execution timed out 113 ms 5840 KB Time limit exceeded
19 Execution timed out 112 ms 6012 KB Time limit exceeded
20 Execution timed out 167 ms 5992 KB Time limit exceeded