Submission #832671

#	Time	Username	Problem	Language	Result	Execution time	Memory
832671		rainboy	Fuel Station (NOI20_fuelstation)	C11	100 / 100	221 ms	31296 KiB

FuelStation

#include <stdio.h>

#define N	300001
#define N_	(1 << 19)	/* N_ = pow2(ceil(log2(N))) */

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 xx[N], aa[N], bb[N], ii[N], idx[N], n;

int *vv;

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 (vv[ii[j]] == vv[i_])
				j++;
			else if (vv[ii[j]] < vv[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;
	}
}

long long ss[N_ * 2], pp[N_ * 2]; int n_;

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

	ss[i] = ss[l] + ss[r];
	pp[i] = max(pp[l], pp[r] - ss[l]);
}

void build() {
	int i;

	n_ = 1;
	while (n_ < n)
		n_ <<= 1;
	for (i = 0; i < n_; i++)
		if (i < n)
			ss[n_ + i] = aa[ii[i]], pp[n_ + i] = xx[ii[i]];
		else
			ss[n_ + i] = 0, pp[n_ + i] = 0;
	for (i = n_ - 1; i > 0; i--)
		pul(i);
}

void update(int i) {
	ss[i += n_] = 0;
	while (i > 1)
		pul(i >>= 1);
}

int main() {
	int x_, i;

	scanf("%d%d", &n, &x_);
	for (i = 0; i < n; i++)
		scanf("%d%d%d", &xx[i], &aa[i], &bb[i]);
	xx[n] = x_, aa[n] = 0, bb[n] = 0;
	n++;
	for (i = 0; i < n; i++)
		ii[i] = i;
	vv = xx, sort(ii, 0, n);
	for (i = 0; i < n; i++)
		idx[ii[i]] = i;
	build();
	vv = bb, sort(ii, 0, n);
	for (i = 0; i < n; i++) {
		if (pp[1] <= bb[ii[i]]) {
			printf("%lld\n", pp[1]);
			return 0;
		}
		update(idx[ii[i]]);
	}
	printf("%lld\n", pp[1]);
	return 0;
}

Compilation message (stderr)

FuelStation.c: In function 'main':
FuelStation.c:70:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |  scanf("%d%d", &n, &x_);
      |  ^~~~~~~~~~~~~~~~~~~~~~
FuelStation.c:72:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |   scanf("%d%d%d", &xx[i], &aa[i], &bb[i]);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 13 / 13
• Subtask 3: 17 / 17
• Subtask 4: 12 / 12
• Subtask 5: 19 / 19
• Subtask 6: 11 / 11
• Subtask 7: 21 / 21