Submission #382591

#	Time	Username	Problem	Language	Result	Execution time	Memory
382591		rainboy	Strange Device (APIO19_strange_device)	C11	5 / 100	582 ms	27856 KiB

strange_device

#include <stdio.h>

#define N	1000000

unsigned int X = 12345;

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

long long gcd(long long a, long long b) {
	return b == 0 ? a : gcd(b, a % b);
}

long long xx[N * 2], yy[N * 4];

int compare_xy(int i, int j) {
	return xx[i] != xx[j] ? (xx[i] < xx[j] ? -1 : 1) : (yy[i] == yy[j] ? 0 : (yy[i] < yy[j] ? -1 : 1));
}

int compare_x(int i, int j) {
	return xx[i] == xx[j] ? 0 : (xx[i] < xx[j] ? -1 : 1);
}

int compare_y(int i, int j) {
	return yy[i] == yy[j] ? 0 : (yy[i] < yy[j] ? -1 : 1);
}

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 main() {
	static int ll[N], rr[N], ii[N * 4], kk[N * 2];
	int n, n_, i, small, x, cnt;
	long long a, b, c, ans;

	scanf("%d%lld%lld", &n, &a, &b), c = a / gcd(a, b + 1);
	if (n == 1) {
		long long l, r;

		scanf("%lld%lld", &l, &r);
		printf("%lld\n", c <= (r - l + 1) / b ? c * b : r - l + 1);
		return 0;
	}
	small = 1;
	for (i = 0; i < n; i++) {
		scanf("%d%d", &ll[i], &rr[i]);
		if (rr[i] - ll[i] + 1 > b)
			small = 0;
	}
	if (!small) {
		n_ = 0;
		for (i = 0; i < n; i++)
			while (ll[i] <= rr[i]) {
				xx[n_] = (ll[i] + ll[i] / b) % a, yy[n_] = ll[i] % b, n_++;
				ll[i]++;
			}
		n = n_;
		for (i = 0; i < n; i++)
			ii[i] = i;
		compare = compare_xy, sort(ii, 0, n);
		ans = 1;
		for (i = 1; i < n; i++)
			if (xx[ii[i]] != xx[ii[i - 1]] || yy[ii[i]] != yy[ii[i - 1]])
				ans++;
	} else {
		n_ = 0;
		for (i = 0; i < n; i++)
			if (ll[i] / b == rr[i] / b)
				xx[n_] = ll[i] / b * (b + 1) % a, yy[n_ << 1 | 0] = ll[i] % b, yy[n_ << 1 | 1] = rr[i] % b + 1, n_++;
			else {
				xx[n_] = ll[i] / b * (b + 1) % a, yy[n_ << 1 | 0] = ll[i] % b, yy[n_ << 1 | 1] = b, n_++;
				xx[n_] = rr[i] / b * (b + 1) % a, yy[n_ << 1 | 0] = 0, yy[n_ << 1 | 1] = rr[i] % b + 1, n_++;
			}
		for (i = 0; i < n_; i++)
			ii[i] = i;
		compare = compare_x, sort(ii, 0, n_);
		for (i = 0, x = 0; i < n_; i++)
			xx[ii[i]] = i + 1 == n_ || xx[ii[i + 1]] != xx[ii[i]] ? x++ : x;
		for (i = 0; i < n_ * 2; i++)
			ii[i] = i;
		compare = compare_y, sort(ii, 0, n_ * 2);
		ans = 0, cnt = 0;
		for (i = 0; i + 1 < n_ * 2; i++) {
			int i_ = ii[i], x = xx[i_ >> 1];

			if ((i_ & 1) == 0) {
				if (kk[x]++ == 0)
					cnt++;
			} else {
				if (--kk[x] == 0)
					cnt--;
			}
			ans += (yy[ii[i + 1]] - yy[ii[i]]) * cnt;
		}
	}
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

strange_device.c: In function 'main':
strange_device.c:58:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   58 |  scanf("%d%lld%lld", &n, &a, &b), c = a / gcd(a, b + 1);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.c:62:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   62 |   scanf("%lld%lld", &l, &r);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.c:68:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   68 |   scanf("%d%d", &ll[i], &rr[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 5 / 5
• Subtask 3: 0 / 5
• Subtask 4: 0 / 5
• Subtask 5: 0 / 5
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20
• Subtask 8: 0 / 30