Submission #536660

#	Time	Username	Problem	Language	Result	Execution time	Memory
536660		rainboy	허수아비 (JOI14_scarecrows)	C11	100 / 100	474 ms	10164 KiB

scarecrows

#include <stdio.h>
#include <string.h>

#define N	200000
#define N_	(1 << 18)	/* N_ = pow2(ceil(log2(N + 1))) */

int max(int a, int b) { return a > b ? a : b; }

unsigned int X = 12345;

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

int *zz;

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)
			if (zz[ii[j]] == zz[i_])
				j++;
			else if (zz[ii[j]] < zz[i_]) {
				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 yy[N_ * 2], kk[N_ * 2], n_;

void build(int n) {
	n_ = 1;
	while (n_ <= n)
		n_ <<= 1;
	memset(yy, -1, n_ * 2 * sizeof *yy);
}

int count(int i, int y) {
	int k = 0;

	while (i < n_)
		if (y >= yy[i << 1 | 1])
			i = i << 1 | 0;
		else
			k += kk[i] - kk[i << 1 | 1], i = i << 1 | 1;
	if (y < yy[i])
		k++;
	return k;
}

void pul(int i) {
	int l = i << 1, r = l | 1;

	yy[i] = max(yy[l], yy[r]);
	kk[i] = kk[r] + count(l, yy[r]);
}

void update(int i, int y) {
	i += n_;
	yy[i] = y, kk[i] = 1;
	while (i > 1)
		pul(i >>= 1);
}

int query(int r) {
	int l = 0, y = -1, k = 0;

	for (l += n_, r += n_; l <= r; l >>= 1, r >>= 1)
		if ((r & 1) == 0)
			k += count(r, y), y = max(y, yy[r]), r--;
	return k;
}

int main() {
	static int xx[N], yy[N], ii[N];
	int n, i, i_;
	long long cnt;

	scanf("%d", &n);
	for (i = 0; i < n; i++)
		scanf("%d%d", &xx[i], &yy[i]);
	for (i = 0; i < n; i++)
		ii[i] = i;
	zz = xx, sort(ii, 0, n);
	for (i = 0; i < n; i++)
		xx[ii[i]] = i;
	zz = yy, sort(ii, 0, n);
	build(n);
	cnt = 0;
	for (i = 0; i < n; i++) {
		i_ = ii[i];
		cnt += query(xx[i_]);
		update(xx[i_], yy[i_]);
	}
	printf("%lld\n", cnt);
	return 0;
}

Compilation message (stderr)

scarecrows.c: In function 'main':
scarecrows.c:86:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
scarecrows.c:88:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |   scanf("%d%d", &xx[i], &yy[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 85 / 85