Submission #382585

#	Time	Username	Problem	Language	Result	Execution time	Memory
382585		rainboy	Strange Device (APIO19_strange_device)	C11	15 / 100	546 ms	40044 KiB

strange_device

#include <stdio.h>

#define N	1000000

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

unsigned int X = 12345;

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

long long xx[N], yy[N];

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) {
			long long c = xx[ii[j]] != xx[i_] ? xx[ii[j]] - xx[i_] : yy[ii[j]] - yy[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 ii[N];
	int n, n_, i, ans;
	long long a, b;

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

		scanf("%lld%lld", &l, &r);
		k = a / gcd(a, b + 1);
		printf("%lld\n", k <= (r - l + 1) / b ? k * b : r - l + 1);
		return 0;
	}
	n_ = 0;
	while (n--) {
		long long l, r;

		scanf("%lld%lld", &l, &r);
		while (l <= r) {
			xx[n_] = (l + l / b) % a, yy[n_] = l % b, n_++;
			l++;
		}
	}
	n = n_;
	for (i = 0; i < n; i++)
		ii[i] = i;
	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++;
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

strange_device.c: In function 'main':
strange_device.c:44:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   44 |  scanf("%d%lld%lld", &n, &a, &b);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.c:48:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   48 |   scanf("%lld%lld", &l, &r);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.c:57:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   57 |   scanf("%lld%lld", &l, &r);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 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