Submission #875883

#	Time	Username	Problem	Language	Result	Execution time	Memory
875883		rainboy	Wish (LMIO19_noras)	C++17	100 / 100	104 ms	9388 KiB

noras

#include <math.h>
#include <stdio.h>

#define N	200000

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

typedef long double ld;
typedef __int128_t L;

unsigned int X = 12345;

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

long long tt[N * 2];

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 = tt[ii[j]] != tt[i_] ? (tt[ii[j]] < tt[i_] ? -1 : 1) : (ii[j] & 1) - (i_ & 1);

			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 * 2];
	int n, n_, i, d, ans;
	long long r;

	scanf("%d%lld", &n, &r);
	n_ = 0;
	while (n--) {
		long long x1, y1, x2, y2, a, b, c, t1, t2;
		ld d;

		scanf("%lld%lld%lld%lld", &x1, &y1, &x2, &y2), x2 -= x1, y2 -= y1;
		a = x2 * x2 + y2 * y2, b = (x1 * x2 + y1 * y2) * 2, c = x1 * x1 + y1 * y1 - r * r;
		d = (ld) b * b - (ld) 4 * a * c;
		if (d < 0)
			continue;
		d = sqrtl(d);
		t1 = (-b - d) / 2 / a, t2 = (-b + d) / 2 / a;
		while ((L) 2 * a * (t1 - 1) + b > 0 || ((L) a * (t1 - 1) + b) * (t1 - 1) + c <= 0)
			t1--;
		while ((L) 2 * a * t1 + b <= 0 && ((L) a * t1 + b) * t1 + c > 0)
			t1++;
		while ((L) 2 * a * (t2 + 1) + b <= 0 || ((L) a * (t2 + 1) + b) * (t2 + 1) + c <= 0)
			t2++;
		while ((L) 2 * a * t2 + b > 0 && ((L) a * t2 + b) * t2 + c > 0)
			t2--;
		t1 = max(t1, 0);
		if (t1 <= t2)
			tt[n_ << 1 | 0] = t1, tt[n_ << 1 | 1] = t2, n_++;
	}
	n = n_;
	for (i = 0; i < n * 2; i++)
		ii[i] = i;
	sort(ii, 0, n * 2);
	d = 0, ans = 0;
	for (i = 0; i < n * 2; i++)
		ans = max(ans, d += ((ii[i] & 1) == 0 ? 1 : -1));
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

noras.cpp: In function 'int main()':
noras.cpp:46:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |  scanf("%d%lld", &n, &r);
      |  ~~~~~^~~~~~~~~~~~~~~~~~
noras.cpp:52:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |   scanf("%lld%lld%lld%lld", &x1, &y1, &x2, &y2), x2 -= x1, y2 -= y1;
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 23 / 23
• Subtask 2: 23 / 23
• Subtask 3: 15 / 15
• Subtask 4: 32 / 32
• Subtask 5: 7 / 7