제출 #493307

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
493307		rainboy	Autobahn (COI21_autobahn)	C11	100 / 100	159 ms	17452 KiB

autobahn

#include <stdio.h>

#define N	100000

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

void accumulate(int *xx, int *dd, int n) {
	static int xx_[N * 2], dd_[N * 2], ii[N * 2];
	int i;

	for (i = 0; i < n; i++)
		ii[i] = i;
	zz = xx, sort(ii, 0, n);
	for (i = 1; i < n; i++)
		dd[ii[i]] += dd[ii[i - 1]];
	for (i = 0; i < n; i++)
		xx_[i] = xx[ii[i]], dd_[i] = dd[ii[i]];
	for (i = 0; i < n; i++)
		xx[i] = xx_[i], dd[i] = dd_[i];
}

int main() {
	static int ll[N], rr[N], cc[N], xx1[N * 2], dd1[N * 2], xx2[N * 2], dd2[N * 2], xx3[N * 8], dd3[N * 8], ii[N * 8];
	int n, n1, n2, n3, k, len, i, i1, i2;
	long long ans, y, d;

	scanf("%d%d%d", &n, &k, &len);
	for (i = 0; i < n; i++)
		scanf("%d%d%d", &ll[i], &cc[i], &rr[i]);
	n1 = 0, n2 = 0;
	for (i = 0; i < n; i++) {
		xx1[n1] = ll[i], dd1[n1] = 1, n1++, xx1[n1] = rr[i] + 1, dd1[n1] = -1, n1++;
		if (ll[i] + cc[i] <= rr[i])
			xx2[n2] = ll[i] + cc[i], dd2[n2] = 1, n2++, xx2[n2] = rr[i] + 1, dd2[n2] = -1, n2++;
	}
	accumulate(xx1, dd1, n1);
	accumulate(xx2, dd2, n2);
	i1 = 0, i2 = 0, n3 = 0;
	while (i1 + 1 < n1 && i2 + 1 < n2) {
		int l = max(xx1[i1], xx2[i2]), r = min(xx1[i1 + 1], xx2[i2 + 1]);

		if (l < r && dd1[i1] >= k && dd2[i2] > 0) {
			xx3[n3] = l - len, dd3[n3] = dd2[i2], n3++, xx3[n3] = l, dd3[n3] = -dd2[i2], n3++;
			xx3[n3] = r - len, dd3[n3] = -dd2[i2], n3++, xx3[n3] = r, dd3[n3] = dd2[i2], n3++;
		}
		if (xx1[i1 + 1] < xx2[i2 + 1])
			i1++;
		else
			i2++;
	}
	for (i = 0; i < n3; i++)
		ii[i] = i;
	zz = xx3, sort(ii, 0, n3);
	ans = 0, y = 0, d = 0;
	for (i = 0; i + 1 < n3; i++) {
		d += dd3[ii[i]];
		y += (long long) (xx3[ii[i + 1]] - xx3[ii[i]]) * d;
		ans = max(ans, y);
	}
	printf("%lld\n", ans);
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

autobahn.c: In function 'main':
autobahn.c:55:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |  scanf("%d%d%d", &n, &k, &len);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
autobahn.c:57:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |   scanf("%d%d%d", &ll[i], &cc[i], &rr[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 50 / 50