Submission #1058694

#	Time	Username	Problem	Language	Result	Execution time	Memory
1058694		rainboy	Naval battle (CEOI24_battle)	C11	100 / 100	262 ms	32228 KiB

Main

#include <stdio.h>

#define N	200000
#define M	(N * 12)

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

unsigned int Z = 12345;

int rand_() {
	return (Z *= 3) >> 1;
}

int dx[] = { 0, 1, 0, -1 };
int dy[] = { -1, 0, 1, 0 };

int xx[N], yy[N], uu[N], vv[N], dd[N], n;

int compare_uv(int i, int j) {
	return uu[i] != uu[j] ? uu[i] - uu[j] : vv[i] - vv[j];
}

int compare_xy(int i, int j) {
	return xx[i] != xx[j] ? xx[i] - xx[j] : yy[i] - yy[j];
}

int (*compare)(int, int);

void sort(int *ii, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;

		while (j < k) {
			int c = compare(ii[j], i_);

			if (c == 0)
				j++;
			else if (c < 0) {
				tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
			}
		}
		sort(ii, l, i);
		l = k;
	}
}

int ii[M], jj[M], tt[M], m;
int iq[M + 1], pq[M], cnt;

int lt(int h1, int h2) { return tt[h1] < tt[h2]; }

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);
}

int pq_first() {
	return iq[1];
}

void pq_remove_first() {
	int i = iq[1], j = iq[cnt--];

	if (j != i)
		pq[j] = 1, pq_dn(j);
	pq[i] = 0;
}

void add(int i, int j) {
	if (i != -1 && j != -1) {
		int t = (abs_(xx[j] - xx[i]) + abs_(yy[j] - yy[i])) / 2;

		if (xx[i] + dx[dd[i]] * t == xx[j] + dx[dd[j]] * t && yy[i] + dy[dd[i]] * t == yy[j] + dy[dd[j]] * t)
			ii[m] = i, jj[m] = j, tt[m] = t, pq_add(m++);
	}
}

char dead[N]; int pp[N][6], qq[N][6];

void kill_(int i) {
	int h;

	if (dead[i])
		return;
	dead[i] = 1;
	for (h = 0; h < 6; h++) {
		int p = pp[i][h], q = qq[i][h];

		if (p != -1 && q != -1)
			qq[p][h] = q, pp[q][h] = p, add(p, q);
	}
}

int main() {
	static int hh[M];
	int cnt_, h, i, j, r, t, tmp;

	scanf("%d", &n);
	for (i = 0; i < n; i++) {
		static char s[2];

		scanf("%d%d%s", &xx[i], &yy[i], s);
		if (s[0] == 'N')
			dd[i] = 0;
		else if (s[0] == 'E')
			dd[i] = 1;
		else if (s[0] == 'S')
			dd[i] = 2;
		else
			dd[i] = 3;
	}
	for (i = 0; i < n; i++)
		for (h = 0; h < 6; h++)
			pp[i][h] = qq[i][h] = -1;
	for (r = 0; r < 4; r++) {
		for (i = 0; i < n; i++)
			ii[i] = i;
		for (i = 0; i < n; i++)
			uu[i] = xx[i] + yy[i], vv[i] = xx[i] - yy[i];
		compare = compare_uv, sort(ii, 0, n);
		for (h = 0, i = -1; h < n; h++) {
			j = ii[h];
			if (dd[j] == 1 || dd[j] == 2) {
				if (i != -1)
					qq[i][r] = j, pp[j][r] = i;
				i = j;
			}
		}
		if (r < 2) {
			compare = compare_xy, sort(ii, 0, n);
			for (h = 0, i = -1; h < n; h++) {
				j = ii[h];
				if (dd[j] == 0 || dd[j] == 2) {
					if (i != -1)
						qq[i][4 + r] = j, pp[j][4 + r] = i;
					i = j;
				}
			}
		}
		for (i = 0; i < n; i++) {
			tmp = -xx[i], xx[i] = yy[i], yy[i] = tmp;
			dd[i] = (dd[i] + 1) % 4;
		}
	}
	m = 0;
	for (i = 0; i < n; i++)
		for (h = 0; h < 6; h++)
			add(i, qq[i][h]);
	while (cnt) {
		h = pq_first(), t = tt[h];
		if (dead[ii[h]] || dead[jj[h]]) {
			pq_remove_first();
			continue;
		}
		cnt_ = 0;
		while (cnt && tt[h = pq_first()] == t) {
			pq_remove_first();
			if (!dead[ii[h]] && !dead[jj[h]])
				hh[cnt_++] = h;
		}
		while (cnt_--) {
			h = hh[cnt_];
			kill_(ii[h]), kill_(jj[h]);
		}
	}
	for (i = 0; i < n; i++)
		if (!dead[i])
			printf("%d\n", i + 1);
	return 0;
}

Compilation message (stderr)

Main.c: In function 'main':
Main.c:121:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  121 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
Main.c:125:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
  125 |   scanf("%d%d%s", &xx[i], &yy[i], s);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 6 / 6
• Subtask 2: 12 / 12
• Subtask 3: 8 / 8
• Subtask 4: 11 / 11
• Subtask 5: 9 / 9
• Subtask 6: 30 / 30
• Subtask 7: 24 / 24